tonic

Etymology 1

From Ancient Greek τονικός (tonikós), from τόνος (tónos). 17th century writers believed health to be derived from firmly stretched muscles, thus tonic; the extension of tonic medicine appeared in the late 18th century. Surface analysis as classical compound: tone + -ic.

adj

1. (physics, pathology) Pertaining to tension, especially of 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, Thomas Pynchon, Inherent Vice, Vintage, published 2010, page 316
2. Restorative, curative or invigorating.
   The arrival of the new members had a tonic effect on the team.
3. (medicine, neuroscience) 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).

noun

1. A substance with medicinal properties intended to restore or invigorate.
   We used to brew a tonic from a particular kind of root.
2. Tonic water.
3. (US, Eastern Massachusetts, dated) Any of various carbonated, non-alcoholic beverages; soda pop.
4. (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, “She's So Modern”, performed by The Boomtown Rats
   'You're a tonic, Dee,' she said. 'And a real friend. Thanks.' 2011, Cathy Kelly, She's the One
   The result is the perfect tonic for Newcastle, coming at the end of a week that saw the departure of Andy Carroll to Liverpool on Monday and an injury to Shola Ameobi during Wednesday's defeat at Fulham. February 5, 2011, Paul Fletcher, “Newcastle 4 - 4 Arsenal”, in BBC

verb

1. (medicine, archaic) To restore or invigorate.
   When all signs of effusion, dulness, pain, œgophony, and cough had disappeared he was dieted, stimulated, and tonicked. 1887, Medical Press and Circular, volume 94, page 461
   The Persians, as a nation, were first to discover that fish were edible. The time is fixed at about 3000 B.C. This was their secret for some centuries—until the Assyrians learned about the elegance of fish for tonicking the brain. 1939, Frank Grant Menke, Encyclopedia of Sports, page 17

Etymology 2

From tone + -ic.

adj

1. (music) Pertaining to or based upon the first note of a diatonic scale.
2. Pertaining to the accent or stress in a word or in speech.
3. 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.

noun

1. (music) The first note of a diatonic scale; the keynote.
2. (music) The triad built on the tonic note.
3. (phonetics) A tonic element or letter; a vowel or a diphthong.