Aperture means an opening, such as a hole, slit or gap.
Aperture is a noun.
Synonyms: gap, fissure, slot, space, orifice, rift.
A camera's aperture is an opening inside the camera's lens that limits the quantity of light that can enter.
We could see the money through the small aperture in the purse.
The photographer adjusted the size of the aperture to allow for the bright sunlight to enter.
The button popped off, leaving an aperture in Mr.Ravi's shirt.