The Collaborative International Dictionary
Tetrachotomous
Tetrachotomous \Tet`ra*chot"o*mous\, a. [Gr. te`tracha in four parts + te`mnein to cut.] (Bot.) Having a division by fours; separated into four parts or series, or into series of fours.
Wiktionary
tetrachotomous
a. divide or branching into four equal pieces.