The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, v. t. [OE. trillen; cf. Sw. trilla to roll.]
   To turn round; to twirl. [Obs.] --Gascoigne.
   [1913 Webster]

         Bid him descend and trill another pin.   --Chaucer.
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The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, v. t. [imp. & p. p. Trilled; p. pr. & vb. n.
   Trilling.] [It. trillare; probably of imitative origin.]
   To impart the quality of a trill to; to utter as, or with, a
   trill; as, to trill the r; to trill a note.
   [1913 Webster]

         The sober-suited songstress trills her lay. --Thomson.
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The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, v. i.
   To utter trills or a trill; to play or sing in tremulous
   vibrations of sound; to have a trembling sound; to quaver.
   [1913 Webster]

         To judge of trilling notes and tripping feet. --Dryden.
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The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, n. [It. trillo, fr. trillare. See Trill to
   shake.]
   [1913 Webster]
   1. 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.
      [1913 Webster]

   2. The action of the organs in producing such sounds; as, to
      give a trill to the tongue. d
      [1913 Webster]

   3. (Mus.) 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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, v. i. [OE. trillen to roll, turn round; of Scand.
   origin; cf. Sw. trilla to roll, Dan. trilde, Icel.
   [thorn]yrla to whirl, and E. thrill. Cf. Thrill.]
   To flow in a small stream, or in drops rapidly succeeding
   each other; to trickle. --Sir W. Scott.
   [1913 Webster]

         And now and then an ample tear trilled down
         Her delicate cheek.                      --Shak.
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         Whispered sounds
         Of waters, trilling from the riven stone. --Glover.
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WordNet (r) 3.0 (2006):

trill
    n 1: a note that alternates rapidly with another note a semitone
         above it [syn: trill, shake]
    2: 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"
    v 1: pronounce with a trill, of the phoneme `r'; "Some speakers
         trill their r's"
    2: sing or play with trills, alternating with the half note
       above or below [syn: warble, trill, quaver]

Moby Thesaurus II by Grady Ward, 1.0:

102 Moby Thesaurus words for "trill":
   Bebung, anthem, babble, ballad, bubble, burble, cackle, call,
   carol, caw, chant, chatter, cheep, chirk, chirp, chirr, chirrup,
   chitter, choir, chorus, chuck, clack, cluck, cock-a-doodle-doo,
   coo, croak, cronk, croon, crow, cuckoo, descant, distill, do-re-mi,
   dribble, drip, drop, drum, falter, flutter, gabble, gaggle, gobble,
   guggle, gurgle, honk, hoo, hoot, hum, hymn, intonate, intone, lap,
   leak, leak out, lilt, minstrel, peep, pip, pipe, plash, psalm,
   purl, quack, quaver, quiver, ripple, roll, roulade, scold,
   serenade, shake, sing, sing in chorus, slosh, sol-fa, solmizate,
   splash, squawk, swash, swish, tremble, tremolando, tremolant,
   tremolo, tremor, trickle, trillet, trilleto, trillo, troll,
   tweedle, tweedledee, tweet, twit, twitter, vibrato, vocalize,
   warble, wash, weep, whistle, yodel



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

TRILL
       Transparent Interconnection of Lots of Links (RFC 5556)