ἡμί-οπος · hēmi-opos — LSJ
with half its holes, with only three holes, something small
with half its holes, ἡ. αὐλοί flutes with only three holes, Anacr. 20; ἡ. (without αὐλός), ὁ, used metaph. of something small, A. Fr. 91.
II
ἡμίοπον· ἥμισυ, Gal. 19.102.