I. ˈtä-nik adjective
Etymology: Greek tonikos, from tonos tension, tone
Date: 1649
1.
a. : characterized by tonus
tonic contraction of muscle
also : marked by prolonged muscular contraction
tonic convulsions
b. : producing or adapted to produce healthy muscular condition and reaction of organs (as muscles)
2.
a. : increasing or restoring physical or mental tone : refreshing
b. : yielding a tonic substance
3. : relating to or based on the first tone of a scale
tonic harmony
4. of a syllable : bearing a principal stress or accent
5. : of or relating to speech tones or to languages using them to distinguish words otherwise identical
• ton·i·cal·ly ˈtä-ni-k(ə-)lē adverb
II. noun
Date: 1797
1. : the first tone of a major or minor scale : keynote
2.
a. : an agent (as a drug) that increases body tone
b. : one that invigorates, restores, refreshes, or stimulates
a day in the country was a tonic for him
c. : a liquid preparation for the scalp or hair
d. chiefly New England : a carbonated flavored beverage
e. : tonic water
3. : a voiced sound