pinnule
/ˈpɪnjuːl/noun
1- Botany a secondary division of a pinnate leaf, especially of a fern【植】二回羽叶, 小羽片。
1.1
- Zoology a part or organ like a small wing or fin, especially a side branch on the arm of a crinoid【动】羽肢; （尤指海百合的）羽状体。
词源
late 16th cent. (denoting one of the sights of an astrolabe)： from Latin pinnula 'small wing', diminutive of pinna.