ternate compound leaf
Botanical term for a compound leaf with three leaflets arising from a common point.
The leaves of mitsuba are a typical example of a ternate compound leaf.
複葉 is a general term for compound leaf, while 三出複葉 specifically refers to a ternate compound leaf with three leaflets.
Compound of 三出 (さんしゅつ, 'three arising') and 複葉 (ふくよう, 'compound leaf'). The exact historical derivation is uncertain, but the term is a straightforward botanical description.