A long, stiff hair growing around the mouth or elsewhere on the face of many mammals, used as a tactile organ; a whisker. The cat's vibrissae twitched as it sensed movement in the dark room.
A feather located near the nostrils of some birds, believed to have a sensory function. The bird's vibrissae helped it detect small insects as it flew through the air.
In certain insects, especially true flies (Diptera), a stiff bristle situated near the mouthparts that serves a sensory function. The entomologist examined the fly under the microscope and measured the length of its vibrissa.