— apertural /ap"euhr choor'euhl/ , adj. — apertured , adj.
/ap"euhr cheuhr/ , n.
1. an opening, as a hole, slit, crack, gap, etc.
2. Also called aperture stop . Optics. an opening, usually circular, that limits the quantity of light that can enter an optical instrument.
[ 1400-50; late ME apertura an opening, equiv. to apert ( us ) opened (ptp. of aperire; aper ( i )- (see APERIENT) + -tus ptp. suffix) + -ura -URE ]