What does acclimatize mean?
Acclimatize is a verb meaning to become accustomed to a new climate or environment, whether that adjustment is physical — as when mountaineers allow their bodies to adapt to reduced oxygen at altitude — or more general, as when newcomers grow comfortable with unfamiliar surroundings or working conditions. The word is most often used with the preposition 'to', as in 'acclimatize to the heat' or 'acclimatize to the altitude'. It carries no strong connotation: it is a neutral, practical term found equally in scientific literature on human physiology and in ordinary conversation about travel or relocation. British English favors acclimatize, while American English more commonly uses the shorter variant acclimate; both are correct. The word derives from 'climate' via French, entering English in the nineteenth century during an era of global exploration, when understanding how humans adjust to different environments became a subject of serious study. Its noun form, acclimatization, remains important in medicine and sports science today.
verbTo become accustomed to a new climate or to new conditions; to adjust physiologically or psychologically to a different environment.
- To become accustomed to a new climate or environmental conditions (especially altitude, temperature, or humidity).
- To become habituated to any new situation, surroundings, or set of circumstances.
"It took the climbers several days to acclimatize to the thin air at high altitude."
"Athletes arriving early for the marathon used the extra week to acclimatize to the city's humid summer heat."
"New employees usually need a few weeks to acclimatize to the fast pace of the trading floor."
The word literally means 'to make like the climate' — it was coined in the 19th century when European scientists were puzzling over why travelers fell ill in the tropics while locals thrived.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of acclimatize
Acclimatize was formed in the early nineteenth century from the noun 'climate', adapted through French 'acclimater', which combined the prefix 'a-' (from Latin 'ad-', meaning 'to') with 'climate'. The term emerged during the period of European colonial expansion and scientific exploration, when naturalists sought to explain how people, plants, and animals adjust to unfamiliar climates. It shares its root with 'climate' itself, from Greek 'klima', meaning 'slope' or 'region of the earth', referring to zones defined by latitude. Cognates include 'climatic' and the related noun 'acclimatization'.
Related word forms
How acclimatize is actually used
Acclimatize is the standard form in British English, while acclimate is preferred in American English; both are fully acceptable. The verb is neutral in register and appears in both scientific writing (physiology, mountaineering) and everyday contexts. It can be used transitively with 'to' (acclimatize to something) or reflexively in sense of becoming adjusted oneself.
Easily confused with acclimatize
Acclimate is the shorter American variant of the same verb, while acclimatize is more common in British English; both mean to become accustomed to new conditions.