hypen (-)

>hyphenation.

[1] Non-hyphenated is an example of a hyphenated word. The hyphen should not be confused with dashes (‒, –, —, ―), which are longer and have different uses, or with the minus sign (−), which is also longer in some contexts.

As an orthographic concept, the hyphen is a single entity. In terms of character encoding and display, that entity is represented by any of several characters and glyphs (including hard hyphens, soft or optional hyphens, and nonbreaking hyphens), depending on the context of use (discussed below).

>Although hyphens are not to be confused with en dashes and minus signs, there are some overlaps in usage (in which either a hyphen or an en dash may be acceptable, depending on user preference; discussed below) and in character encoding (which often uses the same character, called a;hyphen-minus”, to represent both the hyphen and minus sign entities; discussed below).

>The English language does not have definitive hyphenation rules,[4] though various style guides provide detailed usage recommendations, and have a significant amount of overlap in what they advise. Hyphens are mostly used to break single words into parts, or to join ordinarily separate words into single words. Spaces are not placed between a hyphen and either of the elements it connects except when using a suspended or;hanging” hyphen that stands in for a repeated word (e.g., nineteenth- and twentieth-century writers). Style conventions that apply to hyphens (and dashes) have evolved to support ease of reading in complex constructions; editors often accept deviations if they aid rather than hinder easy comprehension.

>The use of the hyphen in English compound nouns and verbs has, in general, been steadily declining. Compounds that might once have been hyphenated are increasingly left with spaces or are combined into one word. Reflecting this changing usage, in 2007, the sixth edition of the Shorter Oxford English Dictionary removed the hyphens from 16,000 entries, such as fig-leaf (now fig leaf), pot-belly (now pot belly) and pigeon-hole (now pigeonhole).[5] The increasing prevalence of computer technology and the advent of the Internet have given rise to a subset of common nouns that might have been hyphenated in the past (e.g. “;toolbar”, “;hyperlink”, “;pastebin”).

>Despite decreased use, hyphenation remains the norm in certain compound-modifier constructions and, among some authors, with certain prefixes (see below). Hyphenation is also routinely used as part of syllabification in justified texts to avoid unsightly spacing (especially in columns with narrow measure, as when used with newspapers).

>Separating
>Justification and line-wrapping
When flowing text, it is sometimes preferable to break a word in half so that it continues on another line rather than moving the entire word to the next line. The word may be divided at the nearest break point between syllables (syllabification), and a hyphen inserted to indicate that the letters form a word fragment, rather than a full word. This allows more efficient use of paper, allows flush appearance of right-side margins (justification) without oddly large word spaces, and decreases the problem of rivers. This kind of hyphenation is most useful when the width of the column (called the measure in typography) is very narrow.

>Prefixes and suffixes
Prefixes (such as de-, pre-, re-, and non-[10]) and suffixes (such as -less, -like, -ness, and -hood) may or may not be hyphenated. (The unhyphenated style is also called closed up or solid.) A rule of thumb is that they are not hyphenated unless the lack of a hyphen hurts clarity—specifically, clarity at first glance rather than clarity upon a second look or a moment’;s pause. The clear–unclear distinction involves some subjectivity, because what is instantly clear to one reader may not be to another (depending on, for example, subject matter familiarity). Nonetheless, consensus among users of a language often reduces that subjectivity for many words. This is explained further below.

>Many long-established words, such as disgusted, degrade, and refresh, do not require a hyphen because they are fully fused to the point that their first syllable is barely even thought about as having a prefix function. Many other words, such as prewashed or repainted, may not be quite so fully fused (the prefix function may be slightly more prominent in consciousness), but nonetheless they require no hyphen, because (1) most readers recognize the closed-up word as a familiar one and thus have no trouble parsing the syllables, and (2) if all such words were hyphenated, the many hyphens throughout the text would seem superfluous.

In contrast, for some other words, the closed-up style may not be as clear, and the hyphen can ensure clarity and avoid awkwardness, including odd appearance or misguided parsing of syllables. An example of avoiding misguided parsing would be to hyphenate the word co-worker (versus coworker) to prevent the reader’;s eye being caught automatically by the letter group cow (which might suggest cow (/kaʊ/) before backtracking and reparsing occurred). In such cases, styling varies depending on individual preference, regional preference, occupational specialty, or style guide preference, because the definition of awkwardness for any given word depends on who is judging it.

>Words for which prefix hyphenation is least subjective, to the point that closed-up style is widely rejected, are of several classes. One such class consists of a few words that require a hyphen to distinguish them from other words that would otherwise be homographs, such as recreation (fun or sport) versus re-creation (the act of creating again), retreat (turn back) versus re-treat (give therapy again), and un-ionized (not in ion form) versus unionized (organized into trade unions). The other classes are those in which the prefix is applied to (1) a proper (capitalized) noun or adjective (un-American, de-Stalinisation);[11][12] (2) an acronym (anti-TNF antibody, non-SI units); or (3) a number (pre-1949 diplomacy, pre-1492 cartography).

>Style guides codify rules to minimize inconsistency, the ultimate goal of which is to have the style unnoticed by the reader (that is, to avoid catching the reader’;s eye, either with trivial differences or with a lot of superfluous hyphens). The style guide rules allow exceptions to avoid awkwardness. For example, a guide will typically say to follow dictionary X’;s style for any word entered therein, and for words not entered, to close up by default and thus hyphenate only to avoid awkwardness. Such a rule successfully codifies almost all choices and thus leaves little to discretion except a few rare or neologistic words, which are safely hyphenated. This ensures high intradocument and interdocument consistency. Rules about avoiding doubled vowels or doubled consonants are often mentioned in style guides. These appropriately cascade only downstream, not upstream, of the;follow dictionary X” rule, because most dictionaries close up many well-established doubled-letter pairs. (For example, any style that follows Merriam-Webster’;s Collegiate Dictionary thus closes up preempt, reexamine, deemphasize, nonnegotiable, posttransfusion, and hundreds of others.) As mentioned earlier, the definition of;awkwardness” for any given word is inherently subjective but nonetheless also subject to consensus. For example, reexamine and deemphasize are accepted as nonawkward by a broad consensus; to prefer the hyphenated styling is a matter of opinion, but to insist that the solid styling is awkward would be considered pedantic by many educated readers. However, some doublings attract smaller majorities than others in such a consensus; with the co-worker/coworker example (mentioned earlier) or with antiinflammatory/anti-inflammatory, many readers may consider solid styling nonawkward whereas plenty of others don’;t, and in such cases, dictionary styles may vary (Dorland’;s, antiinflammatory; Merriam-Webster’;s Medical Dictionary, anti-inflammatory). Tripled letters rarely occur, but when they do, the hyphen is considered mandatory (thus shell-like, not shelllike).

>There is a trend that over decades, words that once were hyphenated for clarity lose the hyphen as their familiarity grows. An excellent example is email/e-mail; the number of people who find email awkward dropped from the 1990s to the 2010s, and thus the hyphen has been dropped increasingly. For some instances, the consensus depends on occupational specialty or subspecialty. Although proto-oncogene is still hyphenated by most users (and by both Dorland’;s and Merriam-Webster’;s Medical), the solid styling (protooncogene) is gaining popularity, with oncologists and geneticists (for whom the term is most familiar) leading the way.

A hyphen can clarify that two adjacent vowels—whether two of the same letter (e.g., oo, ee) or two different letters (e.g., ae, ei)—are pronounced separately rather than being merged in a diphthong. The question is how necessary the clarification is. Thus, hyphenated de-escalate and co-operation have plenty of support, consensus-wise (plenty of users consider their hyphens as not superfluous), although solid deescalate and cooperation have plenty of support as well (plenty of users consider the hyphens superfluous). Consensus for styling varies by class, subclass, and even by individual word, with the common theme being that internal punctuation drops out of any combination judged as instantly recognizable enough in its context not to need it. As classes, there are doubling (namely, aa, ee, ii, oo, uu, yy) and nondoubling (for example, a+e, a+i, a+o; e+e, e+i, e+o). Several subclasses exist. There are combinations that are not rare in English as diphthongs and also not rare as nondiphthongs for users willing to style prefixed words solidly (such as ee and ei); regarding de+e/re+e/pre+e and de+i/re+i/pre+i, nearly everyone agrees that some fully fused examples (such as reiterate and reinforce) need no hyphen, but other examples have more evenly split pluralities (such as reexamine/re-examine or deemphasize/de-emphasize). There are combinations that are rare in English as diphthongs (for example, aa and ii) but not rare in prefixed words for those willing to style them solidly; and thus either they hardly need clarification within prefixed words (the solidification argument; thus intraarterial and antiinflammatory) or they need a hyphen to avoid looking like rare diphthongs, which are “;odd-looking” because rare (the hyphenation argument, thus intra-arterial and anti-inflammatory).

A diaeresis can also sometimes be used, either to indicate nondiphthong status (e.g., coöperation and naïve) or to indicate non-silent terminal -e (e.g., Brontë), but there are several implicit boundaries on this style’;s use; it is now rare (its peak of popularity was in the late 19th and early 20th centuries), and it was never applied extensively across the language (only a handful of examples, including coöperation, naïve, and Brontë, are encountered with any appreciable frequency in English; for whatever reason, it never had any popularity in the de+e/re+e/pre+e or de+i/re+i/pre+i subclasses—thus never *reëxamine, *reïterate, *deëmphasize, or others, although they might have been useful). Many users (and various dictionaries) consider the diaeresis optional in naive/naïve (because not necessary for the reader to recognize the word), and *na-ive draws attention to itself as a style that is simply never used (although comprehensible). For deity and deify, only solid styling (no hyphen or diaeresis) is normative.

>Syllabification and spelling
Hyphens are occasionally used to denote syllabification, as in syl-la-bi-fi-ca-tion. Various British and North American dictionaries use an interpunct, sometimes called a;middle dot” or;hyphenation point”, for this purpose, as in syl·la·bi·fi·ca·tion. This allows the hyphen to be reserved only for places where a hard hyphen is intended (for example, self-con·scious, un·self-con·scious, long-stand·ing). Similarly, hyphens may be used to indicate a word is being or should be spelled. For example, W-O-R-D spells “;word”.

>Joining
>Compound >modifiers
Compound modifiers are groups of two or more words that jointly modify the meaning of another word. When a compound modifier other than an adverb–adjective combination appears before a term, the compound modifier is often hyphenated to prevent misunderstanding, such as in American-football player or little-celebrated paintings. Without the hyphen, there is potential confusion about whether the writer means a;player of American football” or an;American player of football” and whether the writer means paintings that are “;little celebrated” or;celebrated paintings” that are little.[13] Compound modifiers can extend to three or more words, as in ice-cream-flavored candy, and can be adverbial as well as adjectival (spine-tinglingly frightening). However, if the compound is a familiar one, it is usually unhyphenated. For example, at least one style guide prefers the construction high school students, to high-school students.[14] Although the expression is technically ambiguous (“;students of a high school”/”;school students who are high”), it would normally be formulated differently if other than the first meaning were intended. Noun–noun compound modifiers may also be written without a hyphen when no confusion is likely: grade point average and department store manager.[15]

>When a compound modifier follows the term to which it applies, a hyphen is typically not used if the compound is a temporary compound. For example, “;that gentleman is well respected”, not “;that gentleman is well-respected”; ora patient-centered approach was used” but “;the approach was patient centered.”[16] But permanent compounds, found as headwords in dictionaries, are treated as invariable, so if they are hyphenated in the cited dictionary, the hyphenation will be used in both attributive and predicative positions. For example, “A cost-effective method was used” and;The method was cost-effective” (cost-effective is a permanent compound that is hyphenated as a headword in various dictionaries). When one of the parts of the modifier is a proper noun or a proper adjective, there is no hyphen (e.g., “a South American actor”).[17]

>When the first modifier in a compound is an adverb ending in -ly (e.g., “a poorly written novel”), various style guides advise no hyphen.[17][additional citation(s) needed] However, some do allow for this use. For example, The Economist Style Guide advises: “;Adverbs do not need to be linked to participles or adjectives by hyphens in simple constructions …. Less common adverbs, including all those that end -ly, are less likely to need hyphens”.[18] In the 19th century, it was common to hyphenate adverb–adjective modifiers with the adverb ending in -ly (e.g., “a craftily-constructed chair”). However, this has become rare. For example, wholly owned subsidiary and quickly moving vehicle are unambiguous, because the adverbs clearly modify the adjectives: “;quickly” cannot modify “;vehicle”.

>However, if an adverb can also function as an adjective, then a hyphen may be or should be used for clarity, depending on the style guide.[12] For example, the phrase more-important reasons (“;reasons that are more important”) is distinguished from more important reasons (“;additional important reasons”), where more is an adjective. Similarly, more-beautiful scenery (with a mass-noun) is distinct from more beautiful scenery. (In contrast, the hyphen ina more-important reason” is not necessary, because the syntax cannot be misinterpreted.) A few short and common words – such as well, ill, little, and much – attract special attention in this category.[18] The hyphen in;well-[past_participled] noun”, such as in;well-differentiated cells”, might reasonably be judged superfluous (the syntax is unlikely to be misinterpreted), yet plenty of style guides call for it. Because early has both adverbial and adjectival senses, its hyphenation can attract attention; some editors, due to comparison with advanced-stage disease and adult-onset disease, like the parallelism of early-stage disease and early-onset disease. Similarly, the hyphen in little-celebrated paintings clarifies that one is not speaking of little paintings.

>Hyphens are usually used to connect numbers and words in modifying phrases. Such is the case when used to describe dimensional measurements of weight, size, and time, under the rationale that, like other compound modifiers, they take hyphens in attributive position (before the modified noun),[19] although not in predicative position (after the modified noun). This is applied whether numerals or words are used for the numbers. Thus 28-year-old woman and twenty-eight-year-old woman or 32-foot wingspan and thirty-two-foot wingspan, but the woman is 28 years old and a wingspan of 32 feet.[a] However, with symbols for SI units (such as m or kg)—as opposed to the names of these units (such as metre or kilogram)—both the International Bureau of Weights and Measures and the U.S. National Institute of Standards and Technology recommend use without a hyphen: a 25 kg sphere. When the units are spelled out, this recommendation does not apply: a 25-kilogram sphere, a roll of 35-millimeter film.[20][21]

In spelled-out fractions, hyphens are usually used when the fraction is used as an adjective but not when it is used as a noun: thus two-thirds majority[a] and one-eighth portion but I drank two thirds of the bottle or I kept three quarters of it for myself.[22] However, at least one major style guide[19] hyphenates spelled-out fractions invariably (whether adjective or noun).

In English, an en dash ( – ) sometimes replaces the hyphen in hyphenated compounds if either of its constituent parts is already hyphenated or contains a space (for example, San Francisco–area residents, hormone receptor–positive cells, cell cycle–related factors, and public-school–private-school rivalries).[23] A commonly used alternative style is the hyphenated string (hormone-receptor-positive cells, cell-cycle-related factors). (For other aspects of en dash–versus–hyphen use, see Dash > En dash.)

>Object–verbal noun compounds
When an object is compounded with a verbal noun, such as egg-beater (a tool that beats eggs), the result is sometimes hyphenated. Some authors do this consistently, others only for disambiguation; in this case, egg-beater, egg beater, and eggbeater are all common.

An example of an ambiguous phrase appears in they stood near a group of alien lovers, which without a hyphen implies that they stood near a group of lovers who were aliens; they stood near a group of alien-lovers clarifies that they stood near a group of people who loved aliens, as;alien” can be either an adjective or a noun. On the other hand, in the phrase a hungry pizza-lover, the hyphen will often be omitted (a hungry pizza lover), as;pizza” cannot be an adjective and the phrase is therefore unambiguous.

>Similarly, there’;s a man-eating shark in these waters is nearly the opposite of there’;s a man eating shark at table 6; the first is a shark, and the second a man. A government-monitoring program is a program that monitors the government, whereas a government monitoring program is a government program that monitors something else.

>Personal names
Some married couples compose a new surname (sometimes referred to as a double-barrelled name) for their new family by combining their two surnames with a hyphen. Jane Doe and John Smith might become Jane and John Smith-Doe, or Doe-Smith, for instance. In some countries only the woman hyphenates her birth surname, appending her husband’;s surname. (See also Spanish naming customs#Hyphenation and Portuguese name#Hyphenation.)

>With already-hyphenated names, some parts are typically dropped. For example, Aaron Johnson and Samantha Taylor-Wood became Aaron Taylor-Johnson and Sam Taylor-Johnson. Not all hyphenated surnames are the result of marriage. For example Julia Louis-Dreyfus is a descendant of Louis Lemlé Dreyfus whose son was Léopold Louis-Dreyfus.

>Other compounds
Connecting hyphens are used in a large number of miscellaneous compounds, other than modifiers, such as in lily-of-the-valley, cock-a-hoop, clever-clever, tittle-tattle and orang-utan. Use is often dictated by convention rather than fixed rules, and hyphenation styles may vary between authors; for example, orang-utan is also written as orangutan or orang utan, and lily-of-the-valley may or may not be hyphenated.

>Suspended hyphens
A suspended hyphen (also called a;suspensive hyphen” or;hanging hyphen”, or less commonly a;dangling” or;floating” hyphen) may be used when a single base word is used with separate, consecutive, hyphenated words which are connected by;and”, “;or”, orto”. For example, nineteenth-century and twentieth-century may be written as nineteenth- and twentieth-century. This usage is now common in English and specifically recommended in some style guides.[15] Although less common, suspended hyphens are also used in English when the base word comes first, such as in;investor-owned and -operated”. Uses such as;applied and sociolinguistics” (instead of;applied linguistics and sociolinguistics”) are frowned upon in English; the Indiana University Style Guide uses this example and says “;Do not ‘;take a shortcut’ when the first expression is ordinarily open.” (i.e., ordinarily two separate words).[15] This is different, however, from instances where prefixes that are normally closed up (styled solidly) are used suspensively. For example, preoperative and postoperative becomes pre- and postoperative (not pre- and post-operative) when suspended. Some editors prefer to avoid suspending such pairs, choosing instead to write out both words in full.[19]

>Other uses
A hyphen may be used to connect groups of numbers, such as in dates (see below), telephone numbers or sports scores. It can also be used to indicate a range of values, although many styles prefer an en dash (see examples at Dash > En dash > Ranges of values).

>The hyphen is sometimes used to hide letters in words (filleting for redaction/censoring), as in G-d, although an en dash can be used as well (“;G–d”).

>The hyphen is often used in reduplicatives.