The Collaborative International Dictionary of English v.0.48:

Proboscis \Pro*bos"cis\, n.; pl. Proboscides. [L. fr. Gr. ?; ?
   before + ? to feed, graze.]
   1. (Zool.) A hollow organ or tube attached to the head, or
      connected with the mouth, of various animals, and
      generally used in taking food or drink; a snout; a trunk.
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   Note: The proboscis of an elephant is a flexible muscular
         elongation of the nose. The proboscis of insects is
         usually a chitinous tube formed by the modified
         maxill[ae], or by the labium. See Illusts. of
         Hemiptera and Lepidoptera.
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   2. (Zool.) By extension, applied to various tubelike mouth
      organs of the lower animals that can be everted or
      protruded.
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   Note: The proboscis of annelids and of mollusks is usually a
         portion of the pharynx that can be everted or
         protruded. That of nemerteans is a special long
         internal organ, not connected with the mouth, and not
         used in feeding, but capable of being protruded from a
         pore in the head. See Illust. in Appendix.
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   3. The nose. [Jocose]
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   Proboscis monkey. (Zool.) See Kahau.
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