n. In rhetoric, a digressive address; the interruption of the course of a speech or writing, in order to address briefly a person or persons (present or absent, real or imaginary) individually or separately; hence, any abrupt interjectional speech. Originally the term was applied only to such an address made to one present.n. In botany, the arrangement of chlorophyl-granules under the action of direct sunlight (light-apostrophe), and in darkness (dark-apostrophe): in the first case upon the lateral walls of the cells, so that their edges are presented to the light; in the latter, upon the lateral and basal cell-walls: used in distinction from epistrophe (which see).n. In grammar, the omission of one or more letters in a word.n. In writing and printing, the sign (') used to indicate such omission.n. The sign (') used for other purposes, especially, single or double, as a concluding mark of quotation, as in “‘Well done,' said he.” See quotation-mark.