/ Dictionary / Index R respiratory system: Meaning and Definition of Find definitions for: res'piratory sys"tem Pronunciation: [key] — Anat. Anat. the system by which oxygen is taken into the body and an exchange of oxygen and carbon dioxide takes place; in mammals the system includes the nasal passages, pharynx, trachea, bronchi, and lungs. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. respiratory quotient respire Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language