a combining form meaning “world,” “universe,” used in the formation of compound words: cosmography; in contemporary usage, sometimes representing Russian kosmo-, it may mean “outer space,” “space travel,” or “cosmic ray”: cosmonaut.
Also especially before a vowel, cosm-.
Compare astro-.

Origin of cosmo-

< Greek kosmo-, combining form of kósmos cosmos Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for cosmo-


before a vowel cosm-

combining form

indicating the world or universecosmology; cosmonaut; cosmography

Word Origin for cosmo-

from Greek: cosmos
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012