Pin·nate Pin·na·ted a.
1. Bot. Consisting of several leaflets, or separate portions, arranged on each side of a common petiole, as the leaves of a rosebush, a hickory, or an ash. See Abruptly pinnate, and Illust., under Abruptly.
2. Zool. Having a winglike tuft of long feathers on each side of the neck.
Pinnated grouse Zool., the prairie chicken.