Meaning

noun the metaphysical study of the origin and nature of the universe

noun the branch of astrophysics that studies the origin and evolution and structure of the universe

originFrom Medieval Latin cosmologia, from Ancient Greek κόσμος (kósmos, “world”) + -λογία (-logía, “treating of”), combination form of -λόγος (-lógos, “one who speaks (in a certain manner)”). By surface analysis, cosmo- + -logy.

Etymology from Wiktionary, CC BY-SA 3.0