v. re·spired, re·spir·ing, re·spires
1. To breathe in and out; inhale and exhale: respired with difficulty.
2. To carry out the metabolic process of respiration: Different parts of a plant respire at different rates.
3. Archaic To regain one's spirits, as after a period of exertion or trouble.
1. To inhale and exhale (air, for example); breathe.
2. To use (a molecule or compound) for the metabolic process of respiration: bacteria that respire sulfur compounds.
3. To keep (a person or animal) breathing by artificial means: "Becky was still being respired by the ventilator" (Robin Cook).
[Middle English respiren, to breathe again, from Latin respīrāre : re-, re- + spīrāre, to breathe.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.