The Collaborative International Dictionary of English v.0.48:

Neck \Neck\ (n[e^]k), n. [OE. necke, AS. hnecca; akin to D. nek
   the nape of the neck, G. nacken, OHG. nacch, hnacch, Icel.
   hnakki, Sw. nacke, Dan. nakke.]
   1. The part of an animal which connects the head and the
      trunk, and which, in man and many other animals, is more
      slender than the trunk.
      [1913 Webster]

   2. Any part of an inanimate object corresponding to or
      resembling the neck of an animal; as:
      (a) The long slender part of a vessel, as a retort, or of
          a fruit, as a gourd.
      (b) A long narrow tract of land projecting from the main
          body, or a narrow tract connecting two larger tracts.
      (c) (Mus.) That part of a violin, guitar, or similar
          instrument, which extends from the head to the body,
          and on which is the finger board or fret board.
          [1913 Webster]

   3. (Mech.) A reduction in size near the end of an object,
      formed by a groove around it; as, a neck forming the
      journal of a shaft.
      [1913 Webster]

   4. (Bot.) the point where the base of the stem of a plant
      arises from the root.
      [1913 Webster]

   Neck and crop, completely; wholly; altogether; roughly and
      at once. [Colloq.]

   Neck and neck (Racing), so nearly equal that one cannot be
      said to be before the other; very close; even; side by
      side.

   Neck of a capital. (Arch.) See Gorgerin.

   Neck of a cascabel (Gun.), the part joining the knob to the
      base of the breech.

   Neck of a gun, the small part of the piece between the
      chase and the swell of the muzzle.

   Neck of a tooth (Anat.), the constriction between the root
      and the crown.

   Neck or nothing (Fig.), at all risks.

   Neck verse.
      (a) The verse formerly read to entitle a party to the
          benefit of clergy, said to be the first verse of the
          fifty-first Psalm, "Miserere mei," etc. --Sir W.
          Scott.
      (b) Hence, a verse or saying, the utterance of which
          decides one's fate; a shibboleth.

                These words, "bread and cheese," were their neck
                verse or shibboleth to distinguish them; all
                pronouncing "broad and cause," being presently
                put to death.                     --Fuller.

   Neck yoke.
      (a) A bar by which the end of the tongue of a wagon or
          carriage is suspended from the collars of the
          harnesses.
      (b) A device with projecting arms for carrying things (as
          buckets of water or sap) suspended from one's
          shoulders.

   On the neck of, immediately after; following closely; on
      the heel of. "Committing one sin on the neck of another."
      --W. Perkins.

   Stiff neck, obstinacy in evil or wrong; inflexible
      obstinacy; contumacy. "I know thy rebellion, and thy stiff
      neck." --Deut. xxxi. 27.

   To break the neck of, to destroy the main force of; to
      break the back of. "What they presume to borrow from her
      sage and virtuous rules . . . breaks the neck of their own
      cause." --Milton.

   To harden the neck, to grow obstinate; to be more and more
      perverse and rebellious. --Neh. ix. 17.

   To tread on the neck of, to oppress; to tyrannize over.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

neck \neck\, v. i.
   To kiss and caress amorously. [Colloq.] -- n. necking.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Neck \Neck\, v. t. [imp. & p. p. Necked; p. pr. & vb. n.
   Necking.] (Mech.)
   To reduce the diameter of (an object) near its end, by making
   a groove around it; -- used with down; as, to neck down a
   shaft.
   [1913 Webster]

WordNet (r) 3.0 (2006):

neck
    n 1: the part of an organism (human or animal) that connects the
         head to the rest of the body; "he admired her long graceful
         neck"; "the horse won by a neck" [syn: neck, cervix]
    2: a narrow elongated projecting strip of land
    3: a cut of meat from the neck of an animal
    4: a narrow part of an artifact that resembles a neck in
       position or form; "the banjo had a long neck"; "the bottle
       had a wide neck"
    5: an opening in a garment for the neck of the wearer; a part of
       the garment near the wearer's neck [syn: neck, neck
       opening]
    v 1: kiss, embrace, or fondle with sexual passion; "The couple
         were necking in the back seat of the car" [syn: neck,
         make out]