'Apalachee' originates from the Muskogean family of languages (likely from a Hitchiti/Apalachee form such as 'apalahci' or 'apaláchi'), where the element has been interpreted as referring to 'people' or 'people on the other side/over there'.

'Apalachee' was recorded by Spanish explorers as 'Apalache' (or similar forms). The name was later used by Europeans for the region and, through adaptation in Spanish and other languages, contributed to the English regional name 'Appalachian' (via Spanish/French forms) while retaining its reference to the original people.

Initially it referred specifically to the tribe and their language; over time related forms of the name were also applied to geographical regions (e.g., 'Appalachia') and used adjectivally (e.g., 'Appalachian').