- any of the smallest divisions of a leaf which is doubly compound, esp. in ferns
- any of the lateral branches of the arm of a crinoid
Origin: ModL pinnula < L, dim. of pinna, wing, feather: see pen
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also pin·nu·lanoun pl. pin·nules also pin·nu·lae
- Botany Any of the ultimate leaflets of a bipinnately compound leaf.
- Zoology A featherlike or plumelike organ or part, such as a small fin, or one of the appendages of a crinoid.
Origin: Latin pinnula, diminutive of pinna, feather; see pet- in Indo-European roots.
- pinˈnu·lar adjective
pinnule - Science Definition
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