The Collaborative International Dictionary of English v.0.48:

Tooth \Tooth\ (t[=oo]th), n.; pl. Teeth (t[=e]th). [OE.
   toth,tooth, AS. t[=o][eth]; akin to OFries. t[=o]th, OS. & D.
   tand, OHG. zang, zan, G. zahn, Icel. t["o]nn, Sw. & Dan.
   tand, Goth. tumpus, Lith. dantis, W. dant, L. dens, dentis,
   Gr. 'odoy`s, 'odo`ntos, Skr. danta; probably originally the
   p. pr. of the verb to eat. [root]239. Cf. Eat, Dandelion,
   Dent the tooth of a wheel, Dental, Dentist, Indent,
   Tine of a fork, Tusk. ]
   1. (Anat.) One of the hard, bony appendages which are borne
      on the jaws, or on other bones in the walls of the mouth
      or pharynx of most vertebrates, and which usually aid in
      the prehension and mastication of food.
      [1913 Webster]

   Note: The hard parts of teeth are principally made up of
         dentine, or ivory, and a very hard substance called
         enamel. These are variously combined in different
         animals. Each tooth consist of three parts, a crown, or
         body, projecting above the gum, one or more fangs
         imbedded in the jaw, and the neck, or intermediate
         part. In some animals one or more of the teeth are
         modified into tusks which project from the mouth, as in
         both sexes of the elephant and of the walrus, and in
         the male narwhal.
         In adult man there are thirty-two teeth, composed
         largely of dentine, but the crowns are covered with
         enamel, and the fangs with a layer of bone called
         cementum. Of the eight teeth on each half of each jaw,
         the two in front are incisors, then come one canine,
         cuspid, or dog tooth, two bicuspids, or false molars,
         and three molars, or grinding teeth. The milk, or
         temporary, teeth are only twenty in number, there being
         two incisors, one canine, and two molars on each half
         of each jaw. The last molars, or wisdom teeth, usually
         appear long after the others, and occasionally do not
         appear above the jaw at all.
         [1913 Webster]

               How sharper than a serpent's tooth it is
               To have a thankless child!         --Shak.
         [1913 Webster]

   2. Fig.: Taste; palate.
      [1913 Webster]

            These are not dishes for thy dainty tooth. --Dryden.
      [1913 Webster]

   3. Any projection corresponding to the tooth of an animal, in
      shape, position, or office; as, the teeth, or cogs, of a
      cogwheel; a tooth, prong, or tine, of a fork; a tooth, or
      the teeth, of a rake, a saw, a file, a card.
      [1913 Webster]

   4.
      (a) A projecting member resembling a tenon, but fitting
          into a mortise that is only sunk, not pierced through.
      (b) One of several steps, or offsets, in a tusk. See
          Tusk.
          [1913 Webster]
          [1913 Webster]

   5. (Nat. Hist.) An angular or prominence on any edge; as, a
      tooth on the scale of a fish, or on a leaf of a plant;
      specifically (Bot.), one of the appendages at the mouth of
      the capsule of a moss. See Peristome.
      [1913 Webster]

   6. (Zool.) Any hard calcareous or chitinous organ found in
      the mouth of various invertebrates and used in feeding or
      procuring food; as, the teeth of a mollusk or a starfish.
      [1913 Webster]

   In spite of the teeth, in defiance of opposition; in
      opposition to every effort.

   In the teeth, directly; in direct opposition; in front.
      "Nor strive with all the tempest in my teeth." --Pope.

   To cast in the teeth, to report reproachfully; to taunt or
      insult one with.

   Tooth and nail, as if by biting and scratching; with one's
      utmost power; by all possible means. --L'Estrange. "I
      shall fight tooth and nail for international copyright."
      --Charles Reade.

   Tooth coralline (Zool.), any sertularian hydroid.

   Tooth edge, the sensation excited in the teeth by grating
      sounds, and by the touch of certain substances, as keen
      acids.

   Tooth key, an instrument used to extract teeth by a motion
      resembling that of turning a key.

   Tooth net, a large fishing net anchored. [Scot.]
      --Jamieson.

   Tooth ornament. (Arch.) Same as Dogtooth, n., 2.

   Tooth powder, a powder for cleaning the teeth; a
      dentifrice.

   Tooth rash. (Med.) See Red-gum, 1.

   To show the teeth, to threaten. "When the Law shows her
      teeth, but dares not bite." --Young.

   To the teeth, in open opposition; directly to one's face.
      "That I shall live, and tell him to his teeth ." --Shak.
      [1913 Webster]