(tril) v.t.
1. To sing or play in a quavering or tremulous tone.
2. Phonet. To articulate with a trill.
—v.i.
3. To utter, make, or give forth a quavering or tremulous sound.
4. Music To execute a trill or shake.
—noun
1. A tremulous utterance of successive tones, as of certain insects or birds; a warble.
2. Music A quick alternation of two notes either a tone or a semitone apart; shake.
3. Phonet. A rapid vibration of a speech organ, as of the tip of the tongue against the alveolar ridge or the uvula against the back of the tongue, as in the articulation of rr in Spanish.
4. A consonant or word so uttered. Also spelled thrill. [<Ital. trillare, prob. <Gmc.]

(tril) v.t. & v.i. Archaic
1. To flow or cause to flow in a trickle, as tears.
2. To turn or roll; also, to quiver. [ME trillen <Scand. Cf. Sw. & Norw. trilla roll.]