adjective.
Arranged in or consisting of sets or groups of three, as a compound leaf with three leaflets.
The Century Dictionary and Cyclopedia
Arranged in threes; characterized by an arrangement of parts by threes; in botany, used especially of a compound leaf with three leaflets, or of leaves whorled in threes.
the GNU version of the Collaborative International Dictionary of English
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
(of a leaf shape) consisting of three leaflets or sections
Word Usage
"(Moreton Bay chesnut), a fine species of SARCOCEPHALUS, and a large spreading tree belonging to the natural order RUTACEAE, with ternate leaves, axillary panicles of white flowers, about the size of those of BORONIA PINNATA."