Augment

Augment-v
1-(vti) to grow, or to increase something in number, amount size, strength, or intensity (formal)
2-(vt) in music, to enlarge a perfect or major interval by a semitone

n
in Greek or Sanskrite grammar, a vowel prefixed to a verb, or added to its initial vowel so as to lengthen it into a diphthong, to form a past tense

Synonyms
supplement
add to
enlarge
expand
enhance
increase
boost
bump up
diminish (antonym)