[ton.ic] adj [Gk tonikos, fr. tonos tension, tone] (1649) 1 a: characterized by tonus "~ contraction of muscle"; also: marked by prolonged muscular contraction "~ 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 o n the first tone of a scale "~ 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 adv
[2]tonic n (1799) 1 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 ~ for him" c: a liquid preparation for the scalp or hair d chiefly NewEng: a carbonated flavored beverage e: tonic water
2: the first tone of a diatonic scale: keynote
3: a voiced sound