1. Rhetoric. A figure of speech, by which a speaker or writer suddenly stops in his or her discourse, and turns to address pointedly some person or thing, either present or absent; an exclamatory address. (As explained by Quintilian, apostrophe was directed to a person present; modern use has extended it to the absent or dead (who are for the nonce supposed to be present); but it is by no means confined to these, as sometimes erroneously stated.)

2. Botany. The aggregation of protoplasm and chlorophyll-grains on the cell-walls adjacent to other cells, as opposed to epistrophe when they collect on the free cell-walls.

†1. The omission of one or more letters in a word. Obsolete.

2. The sign (') used to indicate the omission of a letter or letters, as in o'er, thro', can't; and as a sign of the modern English genitive or possessive case, as in boy's, boys', men's, conscience', Moses'.In the latter case, it originally marked merely the omission of e in writing, as in fox's, James's, and was equally common in the nominative plural, esp. of proper names and foreign words (as folio's = folioes); it was gradually disused in the latter, and extended to all possessives, even where e had not been previously written, as in man's, children's, conscience' sake. This was not yet established in 1725.