semipenniform

from The Collaborative International Dictionary of English v.0.48

Semipenniform \Sem`i*pen"ni*form\
   (s[e^]m`[i^]*p[e^]n"n[i^]*f[^o]rm), a. (Anat.)
   Half or partially penniform; as, a semipenniform muscle.
   [1913 Webster]