- A drink that supposedly can make you stronger.
- Ben wanted bigger muscles, so he drank a glass of Beauregard's strength tonic
- Tonic water, a drink made with quinine that is used in cocktails
- Devon went to the bar and ordered a gin and tonic
- (music) The keynote of a song (the note that says what other notes will be sharp or flat)
- (music) Pertaining to the keynote of a song