Dictionary definition · tonic
noun
- lime- or lemon-flavored carbonated water containing quinine
- a sweet drink containing carbonated water and flavoring"in New England they call sodas ‘tonics’"
- (music) the first note of a diatonic scale
- a medicine that strengthens and invigorates
adjective
- of or relating to or producing normal tone or tonus in muscles or tissue"a tonic reflex"
- employing variations in pitch to distinguish meanings of otherwise similar words"Chinese is a tonal language"
- (used of syllables) bearing the principle stress, usually accompanied by a change in pitch"a tonic syllable carries the main stress in a word"
- relating to or being the keynote of a major or minor scale"tonic harmony"
- imparting vitality and energy"the bracing mountain air"
Source: Open English WordNet (CC BY 4.0).