pro·au·li·on \prōˈȯlēən, -ēˌän\noun (pluralproaulions \-nz\ ; orproau·lia \-ēə\) Etymology: Late Greek, from Greek, vestibule, from pro pro- (I) + aulion cottage, chamber, diminutive of aulē court, hall — more at aula : a portico or colonnade that opens into the narthex of a church or temple