The Collaborative International Dictionary
Triternate
Triternate \Tri*ter"nate\, a. [Pref. tri- + ternate.] (Bot.) Three times ternate; -- applied to a leaf whose petiole separates into three branches, each of which divides into three parts which each bear three leafiets.
Wiktionary
triternate
a. (context botany English) Three times ternate; applied to a leaf whose petiole separates into three branches, each of which divides into three parts which each bear three leaflets.