trill

Concise Oxford English Dictionary © 2008 Oxford University Press:
trill/trɪl/

▶noun a quavering or vibratory sound, especially a rapid alternation of sung or played notes.

■ the pronunciation of a consonant, especially r, with rapid vibration of the tongue against the hard or soft palate or the uvula.

▶verb produce or pronounce with a trill.

– derivatives
triller noun.

– origin C17: from Ital. trillo (n.), trillare (v.).