The Collaborative International Dictionary of English v.0.48:

Jib \Jib\ (j[i^]b), n. [Named from its shifting from side to
   side. See Jib, v. i.., Jibe.]
   [1913 Webster]
   1. (Naut.) A triangular sail set upon a stay or halyard
      extending from the foremast or fore-topmast to the
      bowsprit or the jib boom. Large vessels often carry
      several jibs; as, inner jib; outer jib; flying jib; etc.
      [1913 Webster]

   2. (Mach.) The projecting arm of a crane, from which the load
      is suspended.
      [1913 Webster]

   3. One that jibs, or balks; a jibber.
      [Webster 1913 Suppl.]

   4. A stationary condition; a standstill.
      [Webster 1913 Suppl.]

   Jib boom (Naut.), a spar or boom which serves as an
      extension of the bowsprit. It is sometimes extended by
      another spar called the flying jib boom. [Written also
      gib boom.]

   Jib crane (Mach.), a crane having a horizontal jib on which
      a trolley moves, bearing the load.

   Jib door (Arch.), a door made flush with the wall, without
      dressings or moldings; a disguised door.

   Jib header (Naut.), a gaff-topsail, shaped like a jib; a
      jib-headed topsail.

   Jib topsail (Naut.), a small jib set above and outside of
      all the other jibs.

   The cut of one's jib, one's outward appearance. [Colloq.]
      --Sir W. Scott.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Jib \Jib\, v. i. [Connected with jibe; cf. OF. giber to shake.]
   To move restively backward or sidewise, -- said of a horse;
   to balk. [Written also jibb.] [Eng.]
   [1913 Webster] Jib

The Collaborative International Dictionary of English v.0.48:

Jib \Jib\, v. t. & i. [imp. & p. p. Jibbed; p. pr. & vb. n.
   Jibbing.] Also Jibb \Jibb\ [Cf. Jib a sail, Gybe.]
   (Chiefly Naut.)
   To shift, or swing round, as a sail, boom, yard, etc., as in
   tacking.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

jib
    n 1: any triangular fore-and-aft sail (set forward of the
         foremast)
    v 1: refuse to comply [syn: resist, balk, baulk, jib]
    2: shift from one side of the ship to the other; "The sail
       jibbed wildly" [syn: jibe, gybe, jib, change course]