(1):

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

(2):

(n.) 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.

(3):

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

(4):

(v. t.) To turn round; to twirl.

(5):

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

(6):

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

(7):

(n.) 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.