The story
- Proto-Indo-European*ten-
- Proto-Indo-European*tn̥eh₁yéti
- Proto-Italic*tenēō
- Latinteneō
- Early Medieval Latintenīre
- Old Frenchtenir, ~nez
- Middle Englishtennys /teneys /tenis
- English todaytennis
From Middle English tennys, teneys, tenis, from Old French tenez (second-person plural imperative of tenir (“to hold”)).
Etymology from Wiktionary, CC BY-SA 4.0.