inter-menstrŭus, a, um, adj., between two months: lunā intermenstruā, i. e. at the time of new moon, Plin. 18, 32, 75, § 322.
Subst.: intermenstrŭum, i. n. (sc. tempus), the new moon, time of new moon, Varr. R. R. 1, 37, 1; Cic. Rep. 1, 16, 25: tempore intermenstrui, Amm. 20, 3, 11.