Fly"trap (?), n. 1. A trap for catching flies. 2. (Bot.) A plant (Dionæa muscipula), called also Venus's flytrap, the leaves of which are fringed with stiff bristles, and fold together when certain hairs on their upper surface are touched, thus seizing insects that light on them. The insects so caught are afterwards digested by a secretion from the upper surface of the leaves.