Close but not quite, it stands for strategic reconnaissance. It's not stealth. Stealth technology didn't come into existence until the late 80s early 90s

But what if we repurposed it to stand for Scientific Research instead? 🤔

This is the internet. Don't be coming round here stating facts that aren't true.

Yeah that's the important part for sure. 🙄

It was originally the RS-71, for "reconnaissance/strike". (source)

Also, don't forget about the closely-related YF-12 interceptor.