APOSTROPHE (Gr. aroarporbit, turning away; the final e being sounded)  , the name given to an exclamatory rhetorical figure of speech, when a speaker or writer breaks off and addresses some one directly in the vocative . The same word (representing, through the French, the Greek arbvrpoOos rpoo w&ia, the accent of elision) means also the sign (') for the omission of a letter or letters, e.g. in " don't." In physiology, " apostrophe " is used more precisely in connexion with its literal meaning of " turning away," e.g. for movement away from the light, in thecase of the accumulation of chlorophyll-corpuscles on the cells of leaves .