Definition of tonics:
(adj) :
Restorative; curative; or invigorating.
(n) :
A substance with medicinal properties intended to restore or invigorate.
(n) :
Tonic water.
(n) :
(US, Eastern Massachusetts, dated) Any of various carbonated, non-alcoholic beverages; soda pop.
(n) :
(figuratively) Someone or something that revitalises or reinvigorates.
(adj) :
(physics, pathology) Pertaining to tension, especially of the muscles.