/ Dictionary / Index O onto: Meaning and Definition of Find definitions for: on•to Pronunciation: (on't, ôn'- unstressed on't&schwa, ôn'-), [key] — prep. to a place or position on; upon; on: to get onto a horse. in or into a state of awareness about: I'm onto your scheme. —adj. pertaining to a function or map from one set to another set, the range of which is the entire second set. onto- Pronunciation: [key] a combining form meaning “being,” used in the formation of compound words: ontogeny. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ontic onto function Related Content Daily Word Quiz: penurious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language