Definitions

1. verb

to sing or utter the notes of (a tune, especially one of a melody in music) without words, or to make musical sounds with the voice

“She began to vocalise the tune, letting her voice soar.”

2. noun

the act of singing or uttering the notes of a tune without words

“The vocalise was a beautiful, soothing sound.”

3. verb (music)

to write music in which the notes are notated but the rhythm and other characteristics are not specified

“The composer chose to vocalise the melody, leaving the rhythm to the performer.”