Source : Webster's Revised Unabridged Dictionary (1913)

Sing \Sing\, v. i. [imp. {Sung}or {Sang}; p. p. {Sung}; p. pr. &
   vb. n. {Singing}.] [AS. singan; akin to D. zingen, OS. & OHG.
   singan, G. singen, Icel. syngja, Sw. sjunga, Dan. synge,
   Goth. siggwan, and perhaps to E. say, v.t., or cf. Gr. ???
   voice. Cf. {Singe}, {Song}.]
   1. To utter sounds with musical inflections or melodious
      modulations of voice, as fancy may dictate, or according
      to the notes of a song or tune, or of a given part (as
      alto, tenor, etc.) in a chorus or concerted piece.

            The noise of them that sing do I hear. --Ex. xxxii.
                                                  18.

   2. To utter sweet melodious sounds, as birds do.

            On every bough the briddes heard I sing. --Chaucer.

            Singing birds, in silver cages hung.  --Dryden.

   3. To make a small, shrill sound; as, the air sings in
      passing through a crevice.

            O'er his head the flying spear Sang innocent, and
            spent its force in air.               --Pope.

   4. To tell or relate something in numbers or verse; to
      celebrate something in poetry. --Milton.

            Bid her . . . sing Of human hope by cross event
            destroyed.                            --Prior.

Singing \Sing"ing\,
   a. & n. from {Sing}, v.

   {Singing bird}. (Zo["o]l.)
   (a) Popularly, any bird that sings; a song bird.
   (b) Specifically, any one of the Oscines.

   {Singing book}, a book containing music for singing; a book
      of tunes.

   {Singing falcon} or {hawk}. (Zo["o]l.) See {Chanting falcon},
      under {Chanting}.

   {Singing fish} (Zo["o]l.), a California toadfish ({Porichthys
      porosissimus}).

   {Singing flame} (Acoustics), a flame, as of hydrogen or coal
      gas, burning within a tube and so adjusted as to set the
      air within the tube in vibration, causing sound. The
      apparatus is called also {chemical harmonicon}.

   {Singing master}, a man who teaches vocal music.

   {Singing school}, a school in which persons are instructed in
      singing.

Source : WordNet®

singing
     adj : smooth and flowing [syn: {cantabile}]
     n 1: the act of singing vocal music [syn: {vocalizing}]
     2: disclosing information or giving evidence about another
        [syn: {tattle}, {telling}]

sing
     v 1: deliver by singing; "Sing Christmas carols"
     2: produce tones with the voice; "She was singing while she was
        cooking"; "My brother sings very well"
     3: to make melodious sounds; "The nightingale was singing"
     4: make a whining, ringing, or whistling sound; "the kettle was
        singing"; "the bullet sang past his ear" [syn: {whistle}]
     5: divulge confidential information or secrets;  "Be
        careful--his secretary talks" [syn: {spill the beans}, {let
        the cat out of the bag}, {talk}, {tattle}, {blab}, {peach},
         {babble}, {babble out}, {blab out}] [ant: {keep quiet}]
     [also: {sung}, {singing}, {sang}]

singing
     See {sing}