/ Dictionary / Index K koi: Meaning and Definition of Find definitions for: koi Pronunciation: (koi), [key] — n. any of various colorful cultivated forms of the common carp, Cyprinus carpio, apparently originating in Japan and other parts of eastern temperate Asia. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Kohoutek koilonychia Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language