The story
- Proto-Indo-European*h₂éd
- Proto-Italic*ad
- Proto-Italic*ad-
- Latinad-
- Old Frencha-
- Frencha-
- Proto-Indo-European*seh₁-redup.
- Proto-Indo-European*sísh₁eti
- Proto-Italic*sizō
- Latinserō
- Latinsatiō
- Old Frenchsaison
- Frenchsaison
- Frenchassaisonner
- Englishseason
- Proto-Indo-European*h₂el-
- Proto-Indo-European*h₂élisder.?
- Englishseasonal
- Proto-Indo-European*leyg-
- Proto-Germanic*līką
- English todayseasonally
From seasonal + -ly.
Etymology from Wiktionary, CC BY-SA 4.0.