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1. Relating to or being the keynote of a major or minor scale
   "tonic harmony"
    
2. Imparting vitality and energy
   "the tonic mountain air";
   - bracing, brisk, fresh, refreshing, refreshful
    
3. (physiology) of or relating to or producing normal tone or tonus in muscles or tissue
   "a tonic reflex"; "tonic muscle contraction"
    
4. Employing variations in pitch to distinguish meanings of otherwise similar words
   "Chinese is a tonic language";
   - tonal
    
5. (used of syllables) bearing the principle stress, usually accompanied by a change in pitch
   "a tonic syllable carries the main stress in a word";
   - accented

1. Lime- or lemon-flavoured carbonated water containing quinine
   - tonic water, quinine water
    
2. A sweet drink containing carbonated water and flavouring
   "in New England they call sodas tonics";
   - pop [N. Amer], soda, soda pop [N. Amer], soda water
    
3. (music) the first note of a diatonic scale
   - keynote
    
4. A medicine that strengthens and invigorates
   - restorative

Derived forms: tonics

See also: invigorating, tonal

Type of: medicament, medication, medicinal drug, medicine, musical note, note, soft drink, tone

Antonym: atonic

Part of: gin and tonic

Encyclopedia: Tonic