summer

English summer comes from Middle English somer, from Old English sumor, from Proto-West Germanic *sumar, from Proto-Germanic *sumaraz, ultimately from Proto-Indo-European *semh₂-.

The word has stayed remarkably stable in form and meaning from Old English sumor straight through to modern English summer, always naming the warm season.

It's cognate with a wide family of words for warmth or time across languages, including Dutch zomer, German Sommer, Swedish sommar, and Welsh haf; further afield, Sanskrit sámā and Armenian am both carry meanings tied to 'year' or 'season,' hinting that the root once measured stretches of time rather than heat itself.