An Etymological Dictionary of Astronomy and Astrophysics

A prefix meaning “down,” also “against; back; by, about; with, along,” occurring originally  in loanwords from Greek; variants cat- and cath-, as in catalog, cataclysm, cataract, cathode, catastrophe, etc.

Etymology (EN): From Gk. kata-, before vowels kat-, from kata “down from, down to.”

Etymology (PE): Katâ-, kâtâ-, kât-, kat-, loan from Gk., as above.