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]