- Damage to biological tissues caused by superoxide and other free radicals generated as a result of intoxication, antimicrobial cellular immunity, metabolic abnormality, or "normal" aging; do not confuse with hypoxia or hyperoxia.
Definition from: CRISP Thesaurus via Unified Medical Language System at the National Library of Medicine
- Physiological stress on the body that is caused by the cumulative damage done by free radicals inadequately neutralized by antioxidants and that is held to be associated with aging.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.