An Etymological Dictionary of Astronomy and Astrophysics

The interval of a complete lunar cycle, between one new Moon and the next, that is 29 days, 12 hours, 44 minutes, and 2.8 seconds. or 29.5306 days. → synodic month.

Etymology (EN): M.E. lunacyon, from M.L. lunation-.

Etymology (PE): Mahâyand, literally “coming, arrival of the Moon,” from mâh→ moon + âyand “coming, arrival,” present stem of âmadan “to come”; O.Pers. aitiy “goes;” Av. ay- “to go, to come,” aēiti “goes;” Skt. e- “to come near,” eti “arrival;” Gk ion " going," neut. pr.p. of ienai “to go;” L. ire “to go;” Goth. iddja “went,” Lith. eiti “to go;” Rus. idti “to go;” from PIE base *ei- “to go, to walk.”