Breadcrumb Home > Dictionary > Index S Siamese fighting fish: Meaning and Definition of Find definitions for: Si'amese fight'ing fish" Pronunciation: [key] a labyrinth fish, Betta splendens, that has been bred for centuries to develop brilliant coloration, very long fins, and pugnacity. See illus. at Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Siamese cat Siamese twins ✖ Related Content Daily Word Quiz: centrifugal Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language