/ Dictionary / Index T thalasso-: Meaning and Definition of Find definitions for: thalasso- Pronunciation: [key] a combining form meaning “sea,” used in the formation of compound words: thalassocracy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thalassic thalassocracy Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language