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