Snake, snare, and snack also come to mind.
You can't make the argument that words starting with sn- must have something to do with noses by reference to developments in the sense of a word that occurred many decades after the word was already current -- or by reference to developments in other parts of the language! By your standard, every word in every language "has to do with the nose".
In this sense, the development of word-senses after word-origination and with respect to developments in other parts of the language would be a fine argument.
I think, sometimes, people are so focused on etymology that they lose sense of why words evolve in meanings over time.
Tracing, for example, the genetics of various finches in the Galapagos, one might find a tree of ancestry and say that "this finch species came from this other, which in turn are derived from this common ancestor" (etymology for birds) -- and that this is why their beak is shaped in such and such a way (because of their ancestral tree).
To do so, however, would be to lose sight of the larger picture -- there are a variety of ecological niches in the galapagos suitable to different beak shapes, and these shapes (like crab body form) have evolved again and again.
The local ecology and niche structure determines a possibility space of beak shapes -- the specifics of which species was capable of competing within those niches as competition waxed and waned in each determines which species were most likely to evolve in which directions (or split and radiate into multiple beak shapes).
We have no problem understanding this for birds -- why is it so hard to conceive of something similar for words?
I'm probably showing my ignorance here, but if etymology and ancestry are paired concepts, what is the name of the word that means "why this word took on this sense", or "why this word stayed in the lexicon and evolved while this other word died out in usage"? The corollary to "evolutionary pressures" on words (and their semantics)?
