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.
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.
2. (Zool.) By extension, applied to various tubelike mouth
organs of the lower animals that can be everted or
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.
3. The nose. [Jocose]
Proboscis monkey. (Zool.) See Kahau.