Pronunciation: (pu-tā'jē-um),[key] —n., —pl.-gi•aPronunciation: (-jē-u).[key] 1. a wing membrane, as of a bat.
2. the extensible fold of skin of certain insects or of a gliding mammal or reptile, as a flying squirrel.
3. either of two small processes on the anterior thorax, found esp. among butterflies and moths.