It is. And outside of contexts where a particular trade or profession uses them as a tool, they're typically called magnifying glasses.

I don't know for certain, but I suspect Adobe introduced its 'loupe tool' in 1987 when it released Photoshop. Whether or not 'loupe' is pretentious, it is now a ubiquitous term in the software industry. It's also four syllables shorter than 'magnifying glass' which, in my view (and when correctly spelled!), absolves it.