Compound three times, the pinnae pinnate and the pinnules pinnate.
Thrice pinnately compound leaf.
Three times pinnate, that is, with first, secondary and tertiary leaflets.
Like bipinnate but carried to one further stage of division, so that the leaflets (of a basically pinnate leaf) are themselves pinnate and the resulting leaflets are again pinnate. Many tree ferns have tripinnate (sometimes even quadripinnate) leaves.