ημιπήχειον

From LSJ

νοεῖν γάρ ἐστι κρεῖττον καὶ σιγὴν ἔχειν → it's better, you see, to understand and yet say nothing (Menander)

Source

Greek Monolingual

ἡμιπήχειον και ἡμιπήχιον, τὸ (Α) ημίπηχυς
μισός πήχυς.