General · EdgepediaSeptember 17, 20266 min read

Apostrophe

The apostrophe ( ' ) is a punctuation mark used in English chiefly to show possession, as in the cat's meow, and to mark omitted letters in contractions, as in don't for do not¹. It is one of the most frequently misused marks in written English, and its rules vary somewhat among style guides⁴.

Key fact	Detail
Main functions	Shows possession (possessives, sometimes called genitives) and marks omitted letters in contractions¹
Etymology	From Greek apostrophos, "turning away", via Late Latin apostrophus and French apostrophe; the punctuation sense is recorded from the 1580s³
Entry into English	Introduced by the mid sixteenth century as a printer's mark, "for the eye rather than for the ear"²
Standardisation	Its use was standardized during the 19th century⁴
Unicode characters	U+2019 RIGHT SINGLE QUOTATION MARK is preferred in set text; U+0027 APOSTROPHE is the keyboard character; U+02BC MODIFIER LETTER APOSTROPHE marks a letter, such as a glottal stop⁵
Common error	Adding an apostrophe to make a plural ("greengrocers' apostrophes"), as in CD's are obsolete⁴^•⁶

Possession

When the first of two consecutive nouns carries an apostrophe, the mark signals a relationship between the nouns. The relationship varies, but all such uses are known collectively as possessives and sometimes as genitives¹.

The placement follows the type of noun doing the possessing¹:

Singular nouns take an apostrophe and s: the committee's report, the bus's passengers.
Plural nouns ending in s take an apostrophe only: both committees' reports, the Joneses' submission.
Plural nouns not ending in s take an apostrophe and s: our children's education, the sheep's wool.
Proper names ending in s take an apostrophe and another s in Australian government style, even when the final s is not pronounced: Burns's report, James's profession, Jesus's disciples¹.
Joint possession takes one apostrophe after the last noun only (Smith and Miller's report), while individual possession takes one after each noun (Smith's and Miller's offices)¹.
Compound nouns place the apostrophe after the whole compound: the attorney-general's speeches, my mother-in-law's dog¹^•⁶.

Style guides differ on singular names ending in s. MLA style adds 's (Athens's history, Alexandre Dumas's novels) while noting that some styles allow only the apostrophe (Athens' history)⁷. Oxford's guide suggests rewording the sentence if adding 's would make a name ending in s or z hard to pronounce⁶.

Apostrophes also mark time expressions that can be paraphrased with of: a week's holiday, three months' notice⁶. When a noun merely describes another noun rather than possessing it, as in workers compensation or visitors book, no apostrophe is used¹.

Contractions

In a contraction, two words are joined into one shorter word and the apostrophe stands where letters have been left out: do not becomes don't, it is becomes it's, cannot becomes can't, and will not becomes won't⁸. The apostrophe goes in the position the omitted letters would have occupied, not where the space between the original words fell⁶.

Some contractions are ambiguous in writing. 's can stand for is or has (She's seen that movie already; He's my brother), and 'd can stand for had or would⁸. The possessive pronoun its takes no apostrophe; it's is a contraction of it is or it has⁸^•⁶^•¹⁰.

Plurals and exceptions

Style guides generally prohibit the apostrophe for plurals of nouns, abbreviations, numbers, and words not usually used as nouns: CVs, the 1990s, two Johns, dos and don'ts⁶. The best-known exception is the plural of lowercase letters, where the apostrophe aids reading: Mind your p's and q's, Accommodation has two c's and two m's⁷. MLA style still omits it for grades and for abbreviations containing capital letters (She got three As; people with MAs and PhDs)⁷.

Misplaced apostrophes in plurals, especially on shop signs, are common enough to have a name, greengrocers' apostrophes, humorously misspelled as "greengrocers apostrophe's"⁴.

History

The word entered English in two senses. The rhetorical sense, "a turning aside of an orator in the course of a speech to address briefly some individual", is recorded from the 1530s; the punctuation sense, "mark indicating an omitted letter", from the 1580s. Both derive from French apostrophe, from Late Latin apostrophus, from Greek apostrophos (prosoidia), "(the accent of) turning away", from apostrephein, "avert, turn away"³.

The mark itself was introduced into the English orthographic system by the mid sixteenth century as a printer's mark designed "for the eye rather than for the ear". Although some early sources derived it from the virgule, it is more plausibly a symbol of Greek and Latin provenance that English most likely borrowed from French and Italian, where it had wide circulation². Early English documents used it from the second half of the sixteenth century, first to mark elision, as in th'onely for the only and o'man for woman, with no consistency in whether the mark stood before or after the point of elision².

Early uses were broader than today's. Besides the Saxon genitive (the woman's book), verbal contractions (you'll, you're), and formulaic expressions (o'clock), early writers used the apostrophe for other cases of elision and for abbreviated words². In English, the mark often represented the loss of the -e- in the -es possessive ending, and by the 18th century it had been extended to all possessives, whether or not they had ever had an -e-³. Its use was standardized during the 19th century, yet the rules still trouble many writers, including literate speakers of English⁴.

Typography and computing

In Unicode, three distinct characters serve apostrophe-like roles. U+0027 APOSTROPHE, the straight vertical mark on most keyboards, is heavily overloaded: in ASCII it can represent several punctuation marks or a modifier letter. When text is set, U+2019 RIGHT SINGLE QUOTATION MARK is preferred as the apostrophe, and it is identical in shape to a closing single quotation mark. Where the apostrophe functions as a letter, for example in transliterations marking a glottal stop, U+02BC MODIFIER LETTER APOSTROPHE is preferred⁵.

Word processors commonly convert the typed U+0027 into a contextually chosen curly glyph, and this "smart quotes" feature cannot always tell an apostrophe from an opening single quotation mark. At the start of a word, as in '70s or 'til, applications tend to supply an opening quote mark where a closing-shaped apostrophe is correct⁹. In almost all typefaces the apostrophe should look like a raised, non-inverted comma in the same typeface⁹.

References

Topic: Encyclopedia › Society and history › Languages and linguistics › Writing and notation systems › Punctuation and orthographic marks

Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026

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