tonic

a medicine that strengthens and invigorates

the first note of a diatonic scale

employing variations in pitch to distinguish meanings of otherwise similar words

lime- or lemon-flavored carbonated water containing quinine

a sweet drink containing carbonated water and flavoring

“in New England they call sodas tonics”

bearing the principle stress, usually accompanied by a change in pitch

“a tonic syllables carries the main stress in a word”

imparting vitality and energy

of or relating to or producing normal tone or tonus in muscles or tissue

“a tonic reflex”

relating to or being the keynote of a major or minor scale

“tonic harmony”