Synonyms: aperture
Definition: an man-made opening; usually small
Similar words: opening
Definition: a vacant or unobstructed space that is man-made
Usage: they left a small opening for the cat at the bottom of the door
Synonyms: aperture
Definition: a device that controls amount of light admitted
Similar words: regulator
Definition: any of various controls or devices for regulating or controlling fluid flow, pressure, temperature, etc.
Synonyms: aperture
Definition: a natural opening in something
Similar words: hole
Definition: an opening into or through something