-mē, -i noun
( -es )
Etymology: Middle English astronomie, from Old French, from Latin astronomia, from Greek, from astronomos astronomer (from astr- + nomos law) + -ia -y — more at nimble
1. : the science that treats of the celestial bodies, of their positions, magnitudes, motions, distances, constitution, physical condition, mutual relations, history, and destiny — formerly used as synonymous with astrology
2. : a treatise on this science