Definitions:
a medicinal substance taken to give a feeling of vigour or well-being.

the first note in a scale which, in conventional harmony, provides the keynote of a piece of music.

giving a feeling of vigour or well-being; invigorating

relating to or denoting the first degree of a scale.

denoting or relating to the syllable within a tone group that has greatest prominence, because it carries the main change of pitch.

relating to or restoring normal tone to muscles or other organs.