My Algorithms lecturer called it the "equivils" symbol, as in "like equals but meaning exactly equivalent to".

I thought that was a standard name until I tried to use it around someone from a different university. I had to google it to prove I wasn't crazy, and when google came up with only four random hits, I was forced to concede that I may well in fact be crazy after all.

I can't decide if he thought equivils was the best name for it, or if he was just trying to make it so we couldn't google solutions to his assignments...