The word autumn comes from the Old French word autompne (automne in modern French), and was later normalized to the original Latin word autumnus. There are rare examples of its use as early as the 12th century, but it became common by the 16th century.

The alternative word fall is now mostly a North American English word for the season. It traces its origins to old Germanic languages. The exact derivation is unclear, the Old English fiæll or feallan and the Old Norse fall all being possible candidates. However, these words all have the meaning "to fall from a height" and are clearly derived either from a common root or from each other. The term came to denote the season in the 16th century, a contraction of Middle English expressions like "fall of the leaf" and "fall of the year".

During the 20th century, English immigration to the colonies in North America was at its lowest point, and the new settlers took their language with them. While the term fall gradually became obsolescent in Britain, it became the more common term in North America, where autumn is nonetheless preferred in scientific and often in literary contexts.