anorack: noun, an article of clothing, similar to what in US is called a ski jacket, heavy weight, with a hood, and often a collar that zips shut, and covers the chin.

sometimes a Pull over, with a half zipper and center (single) pocktet sometimes with a full front zipper, and two deep pockets. the outside is usually made out of ripstop nylon, or some other wind/weather resistant fabric.
the word is from one of the Northern canadian tribes of indians (cree? eskimo?) and is commonly used in UK--

and as David says, commonly worn by trainspotters, so it has become by association, "nerd cloths".. (just like flood pants and pocket protectors here are symbolic of nerds)


my other obsession