A long flexible snout as of an elephant WordNet 3.0 & Open English WordNet

A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. Wikipedia

An elongated tube from the head or connected to the mouth, of an animal. Wiktionary

Elongated tube. Wiktionary (translation)

The conspicuously extended, mobile, nose-like organ of an animal such as a sengi, a tapir or especially an elephant. The trunks of various kinds of animals might be adapted to probing and sniffing, as in the sengis, or be partly prehensile, as in the tapir, or be a versatile prehensile organ for manipulation, feeding, drinking and fighting as in the elephant. Wiktionary