/ Dictionary / Index G gyrase: Meaning and Definition of Find definitions for: gy•rase Pronunciation: ( jī'rās, -rāz), [key] — n. Biochem. a bacterial enzyme that causes supercoiling of DNA. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gyral gyrate Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language