The Collaborative International Dictionary of English v.0.48:

Protrude \Pro*trude"\, v. i.
   To shoot out or forth; to be thrust forward; to extend beyond
   a limit; to project.
   [1913 Webster]

         The parts protrude beyond the skin.      --Bacon.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Protrude \Pro*trude"\, v. t. [imp. & p. p. Protruded; p. pr. &
   vb. n. Protruding.] [L. protrudere, protrusum; pro forward
   + trudere to thrust. See Threat.]
   [1913 Webster]
   1. To thrust forward; to drive or force along. --Locke.
      [1913 Webster]

   2. To thrust out, as through a narrow orifice or from
      confinement; to cause to come forth.
      [1913 Webster]

            When . . . Spring protrudes the bursting gems.
                                                  --Thomson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

protrude
    v 1: extend out or project in space; "His sharp nose jutted
         out"; "A single rock sticks out from the cliff" [syn:
         stick out, protrude, jut out, jut, project]
    2: bulge outward; "His eyes popped" [syn: start, protrude,
       pop, pop out, bulge, bulge out, bug out, come
       out]
    3: swell or protrude outwards; "His stomach bulged after the
       huge meal" [syn: bulge, pouch, protrude]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "protrude":
   arise, bail out, balloon, beetle, belly out, break cover,
   break forth, bristle up, bulge, burst forth, cock up, come,
   come forth, come out, debouch, disembogue, effuse, emanate, emerge,
   erupt, extend, extrude, goggle, issue, issue forth, jump out, jut,
   jut out, overhang, poke, poke out, pouch, pout, project,
   protuberate, sally, sally forth, shoot out, shoot up, stand out,
   start up, stick out, stick up, surface, thrust out