The story
- Proto-Indo-European*h₂éd
- Proto-Italic*ad
- Proto-Italic*ad-
- Latinad-
- Proto-Indo-European*sekʷ-
- Proto-Indo-European*sokʷéh₂
- Proto-Indo-European*sokʷh₂ṓy
- Proto-Indo-European*sokʷyós
- Proto-Italic*sokjos
- Latinsokios
- Latinsocius
- Latinsociō
- Latinassociō
- Latinassociātiō
- English todayassociation
From Latin associātiō, from associō (perhaps via French association). Morphologically associate + -ion. The Philippine sense is a calque of Spanish gremio.
Etymology from Wiktionary, CC BY-SA 4.0.