/ Dictionary / Index D double-helical gear: Meaning and Definition of Find definitions for: dou'ble-hel•i•cal gear' Pronunciation: (dub'ul hel"i-kul). [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. doubleheader double helix Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language