ternate

Arranged in or consisting of sets or groups of three, as a compound leaf with three leaflets.

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.

Having the parts arranged by threes.

Having three divisions (or leaflets)

(of a leaf shape) consisting of three leaflets or sections