Thread: What is this letter in the russian keyboard ->"№"

№ = #
It was a standard number sign in XIX century France, and as such came into Russian typography. It has not changed since then.
Check "Numero sign" article in Wikipedia.

It's a pretty commonly used abbreviation in English, it's just not treated as a character symbol so it doesn't appear on standard keyboards. There used to be a № key on older typewriters though, as far as I remember.