hyphen

A hyphen is a punctuation mark used to join words and to separate syllables within a word at line breaks. It is shorter than an en dash and an em dash, and it is distinct from the minus sign used in mathematics. In many fonts, the hyphen is rendered as a simple short horizontal bar.

Common uses include linking together words to form compound terms (for example, well-known, state-of-the-art), and dividing a word at the end of a line to continue on the next line. Hyphens also serve to prevent ambiguity in certain spellings or constructions, such as re-enter or co-operate, though style guides differ on whether some of these forms should be hyphenated.

In English typography, hyphenation rules are guided by style manuals and can vary by publication. General guidelines include hyphenating compound adjectives when they appear before a noun (a well-known author) and using hyphens to avoid misreading or ambiguity, such as a re-created manuscript. Hyphenate numbers twenty-one through ninety-nine when spelled out. Do not hyphenate most adverbs ending in -ly (for example, highly respected). Some prefixes (anti-, mid-, pre-, non-) are hyphenated in certain contexts to prevent confusion or awkward spelling, but rules differ by style.

Related marks include the en dash (–) and em dash (—), which have different functions, such as ranges or parenthetical statements. In digital text, a soft hyphen (U+00AD) marks a potential break point, while a non-breaking hyphen (U+2011) prevents a break at the hyphen. The typical hyphen character used in plain text is the hyphen-minus (U+002D).