1 (also tonic water) [U] [C] a type of water with bubbles in it and a rather bitter taste that is often added to alcoholic drinks 奎宁水: a gin and tonic 一杯杜松子酒加奎宁水

2 [C,U] a medicine or sth you do that makes you feel stronger, healthier, etc, especially when you are very tired 补药；强身剂；恢复精力的东西: A relaxing holiday is a wonderful tonic. 轻松的假期对身体大有裨益。