What is the meaning of Pinnule?

Any of the ultimate leaflets of a bipinnate or tripinnate leaf; a subleaflet.

A part or an organ which resembles the barb of a feather, particularly the side branches on the stalks of crinoids; Any of the lateral divisions of the finger-like stalks of an encrinite.

allative singular of pind

pinnule

Source: wiktionary.org