trill
US /trɪl/
UK /trɪl/

1.
trillo
a quavering or vibratory sound, especially a rapid alternation between two musical notes a semitone or tone apart
:
•
The bird's song ended with a beautiful trill.
Il canto dell'uccello si concluse con un bel trillo.
•
She added a delicate trill to the melody.
Ha aggiunto un delicato trillo alla melodia.