/ Dictionary / Index B BIOS: Meaning and Definition of Find definitions for: BIOS Pronunciation: (bī'ōs), [key] computer firmware that directs many basic functions of the operating system, as booting and keyboard control. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. biorhythmics biosafety Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language