The story
- Proto-Indo-European*treb-der.?
- Ancient Greekθερᾰ́πων (therắpōn)
- Ancient Greekθεραπεύω (therapeúō)
- Ancient Greekθεραπεία (therapeía)
- New Latintherapīa
- English todaytherapy
From New Latin therapīa, from Ancient Greek θεραπεία (therapeía, “service, medical treatment”), from θεραπεύω (therapeúō, “to serve, treat medically”) + -ία (-ía, suffix for forming abstract nouns).
Etymology from Wiktionary, CC BY-SA 4.0.