• A condition characterized by an abnormally high body temperature. In a hyperthermic state, the hypothalamic set-point is normal but body temperature increases and overrides the ability to lose heat, resulting from exogenous heat exposure or endogenous heat production.
  NCI
  U.S. National Cancer Institute, 2021
• Abnormally high body temperature. This may be caused as part of treatment, by an infection, or by exposure to heat.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• An abnormal elevation of body temperature, usually as a result of inability to regulate core body temperature due to non-pathologic factors.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• An abnormally high body temperature. Not fever.
  U.S. FDA Glossary
  U.S. Food & Drug Administration, 2021
• Elevation of body temperature above normal due to the production or absorption of more heat than the body is able to dissipate.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021