νουμην-ία · noumēn-ia — LSJ
new moon : the first of the month, Pi. l.c., Antipho Fr. 58 (pl.), Ar. Eq. 43, Ach. 999 (pl.), etc. ; ν. κατὰ σελήνην to denote the true or natural new moon, as opp. to the νουμηνία of the calendars, Th. 2.28 ; also ἡ κατὰ θεὸν ν. PMag.Par. 1.787, 2389 ; ν. τοῦ ἔτους, of the spring equinox, Ptol. Tetr. 91.