Definify.com
Webster 1913 Edition
Pinnated
{ 
Pin′nate
,Pin′na-ted
, }Adj.
 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.