Bipennis | Webster's Dictionary of the English Language

bipennis
bĭpennis (-pinnis), e, adj. [bispenna], having two wings , two-winged (very rare): insectum, Pl...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
bipennis
bipennis e, adj.bi-+penna, with two edges, two-edged : ferrum, V.— As subst f . (sc. securis), wit...

An Elementary Latin Dictionary