'normothermia' originates from modern medical coinage combining elements ultimately from Latin and Greek: 'normo-' (from Latin 'norma', meaning 'rule, pattern') and Greek 'thermia' (from Greek 'thermḗ', meaning 'heat').

'normothermia' was formed in modern medical/Latin usage by combining the prefix 'normo-' with Greek-derived 'thermia'; this compound entered English medical vocabulary in the 19th–20th century to denote 'normal heat (state)'.

Initially it referred generally to 'normal heat' in a literal sense; over time it became specialized to mean 'normal body (core) temperature' in medical contexts.