1. a medicine that invigorates or strengthens: a tonic of sulphur and molasses.
  2. anything invigorating physically, mentally, or morally: His cheerful greeting was a real tonic.
  3. quinine water.
  4. Music. the first degree of the scale; the keynote.
  5. Chiefly Eastern New England. soda pop.
  6. Phonetics. a tonic syllable or accent.
  1. pertaining to, maintaining, increasing, or restoring the tone or health of the body or an organ, as a medicine.
  2. invigorating physically, mentally, or morally.
  3. Physiology, Pathology.
    1. pertaining to tension, as of the muscles.
    2. marked by continued muscular tension: a tonic spasm.
  4. using differences in tone or pitch to distinguish between words that are otherwise phonemically identical: a tonic language.
  5. pertaining to tone or accent in speech.
  6. Phonetics. (of a syllable) bearing the principal stress or accent, usually accompanied by a change in pitch.
  7. Music.
    1. of or relating to a tone or tones.
    2. pertaining to or founded on the keynote, or first tone, of a musical scale: a tonic chord.

Origin of tonic

First recorded in 1640–50, tonic is from the Greek word tonikós pertaining to stretching or tones. See tone, -ic
Related formston·i·cal·ly, adverban·ti·ton·ic, adjective, nounnon·ton·ic, adjectivepre·ton·ic, noun, adjective

Synonyms for tonic

Regional variation note

5. See soda pop. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for pretonic


  1. denoting or relating to the syllable before the one bearing the primary stress in a word


  1. a medicinal preparation intended to improve and strengthen the functioning of the body or increase the feeling of wellbeing
  2. anything that enlivens or strengthenshis speech was a tonic to the audience
  3. Also called: tonic water a mineral water, usually carbonated and containing quinine and often mixed with gin or other alcoholic drinks
  4. music
    1. the first degree of a major or minor scale and the tonal centre of a piece composed in a particular key
    2. a key or chord based on this
  5. a stressed syllable in a word
  1. serving to enliven and invigoratea tonic wine
  2. of or relating to a tone or tones
  3. music of or relating to the first degree of a major or minor scale
  4. of or denoting the general effect of colour and light and shade in a picture
  5. physiol of, relating to, characterized by, or affecting normal muscular or bodily tonea tonic spasm
  6. of or relating to stress or the main stress in a word
  7. denoting a tone language
Derived Formstonically, adverb

Word Origin for tonic

C17: from New Latin tonicus, from Greek tonikos concerning tone, from tonos tone
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for pretonic



1640s, "relating to or characterized by muscular tension," from Greek tonikos "of stretching," from tonos "a stretching" (see tenet). The meaning "maintaining the healthy firmness of tissues" is recorded from 1680s, first extended 1756 to "having the property of restoring to health."



"a tonic medicine," 1799, from tonic (adj.).



in the musical sense, 1760, from tone (n.) + -ic. Related: Tonicity.

Online Etymology Dictionary, © 2010 Douglas Harper

pretonic in Medicine


  1. Of or producing tone or tonicity in muscles or tissue.
  2. Characterized by continuous tension or contraction of muscles, as a convulsion or spasm.
  3. Producing or stimulating physical, mental, or emotional vigor.
  1. An agent, such as a medication, that restores or increases body tone.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.