Trill

To flow in a small stream, or in drops rapidly succeeding each other; to trickle.

To turn round; to twirl.

To impart the quality of a trill to; to utter as, or with, a trill; as, to trill the r; to trill a note.

To utter trills or a trill; to play or sing in tremulous vibrations of sound; to have a trembling sound; to quaver.

A sound, of consonantal character, made with a rapid succession of partial or entire intermissions, by the vibration of some one part of the organs in the mouth -- tongue, uvula, epiglottis, or lip -- against another part; as, the r is a trill in most languages.

The action of the organs in producing such sounds; as, to give a trill to the tongue. d

A shake or quaver of the voice in singing, or of the sound of an instrument, produced by the rapid alternation of two contiguous tones of the scale; as, to give a trill on the high C. See Shake.

the articulation of a consonant (especially the consonant ‘r’) with a rapid flutter of the tongue against the palate or uvula; "he pronounced his R's with a distinct trill"