- a wing membrane, as of a bat.
- the extensible fold of skin of certain insects or of a gliding mammal or reptile, as a flying squirrel.
- either of two small processes on the anterior thorax, found especially among butterflies and moths.
- a web of skin between the neck, limbs, and tail in bats and gliding mammals that functions as a wing
- a membranous fold of skin connecting margins of a bird's wing to the shoulder
