tonic UK /ˈtɒnɪk/US /ˈtɑ.nɪk/noun 7adjective 6verb 1forms 5 noun7 •Tonic water. •(US, old-fashioned) Any of various carbonated, non-alcoholic beverages; soda pop. •A substance with medicinal properties intended to restore or invigorate.We used to brew a tonic from a particular kind of root. •(figurative) Someone or something that revitalises or reinvigorates.Charlie ain't no Nazi / She likes to wear her leather boots / 'Cause it's exciting for the veterans / And it's a tonic for the troops. — 1978 •The first note of a diatonic scale; the keynote. •The triad built on the tonic note. •A tonic element or letter; a vowel or a diphthong. adjective6 •Restorative; curative; or invigorating.The arrival of the new members had a tonic effect on the team. •Pertaining to or based upon the first note of a diatonic scale. •Pertaining to tension, especially of the muscles.Out in front and across the street, Doc noted half a dozen or so young men, not loitering or doing substances but poised and tonic, as if waiting for some standing order to take effect. — 2009 •In a state of continuous unremitting action.Peter Redgrave (2007) Basal ganglia. Scholarpedia, 2(6):1825. GABAergic neurones in the basal ganglia output nuclei have high tonic firing rates (40-80 Hz). •Pertaining to the accent or stress in a word or in speech. •Of or relating to tones or sounds; specifically (phonetics, dated) being or relating to a speech sound made with tone unmixed and undimmed by obstruction, i.e. a vowel or diphthong. verb1 •(no longer used) To restore or invigorate.When all signs of effusion, dulness, pain, oegophony, and cough had disappeared he was dieted, stimulated, and tonicked. — 1887 formstonicked · tonicking · tonics · more tonic · most tonic