Origin: 1620–30; < L aperient- (s. of aperiēns opening, prp. of aperīre to open), equiv. to aperi- (appar. ap-, var. of ab-ab-+ -eri-) + -ent--ent; the base -eri-, perh. with an earlier shape *wery- or *twery-, occurs only in this verb and operīre to close (see cover, operculum)