- (also tonic water)[uncountable, countable]
a clear fizzy drink (= with bubbles in it) with a slightly bitter taste, that is often mixed with a strong alcoholic drink, especially gin or vodka 奎宁水，汤力水（一种味微苦、常加于烈性酒中的有气饮料） a gin and tonic 一杯杜松子酒奎宁水
- [countable]
a medicine that makes you feel stronger and healthier, taken especially when you feel tired 补药；滋补品 herbal tonics 滋补草药
- [countable, uncountable]
a liquid that you put on your hair or skin in order to make it healthier 护发液；护肤液 skin tonic 护肤液
- [countable, usually singular] (old-fashioned)
anything that makes people feel healthier or happier 使精神振奋的东西 - [countable] (
music 音乐 the first note of a scale of eight notes 主音（自然音阶中的第一音） - (also tonic syllable)[countable] (
phonetics 语音学 the syllable in a tone unit on which a change in pitch takes place 语调音节，语调核心（区别音高变化的音节）
Word Originmid 17th cent.: from French tonique, from Greek tonikos ‘of or for stretching’, from tonos ‘tension, tone’, from teinein ‘to stretch’.