"Feel the power of knowledge!
Flash drives are called flash drives just like you said, but that's because it's what is easy to use. RAM comes in DDR, DDR2 and DDR3 which basically means "out dated", "just became outdated" and "it's what we have now" in terms of transfer speeds, respectively.
RAM comes in a bajillion types, the main distinctions being SRAM and DRAM. S means static so it behaves like flash or more specifically NAND, while D means dynamic which means it is volatile 'cos it has capacitors which are like "WE NEED ELECTRICITY ALL THE TIME TO DO ANYTHING!""
Of course you're correct, but Flash memory is the generic term used for non volatile RAM these days, hence those non volatile cards you stick in a camera for example are refered to as a flash card often, same as a usb memory stick for a PC.
I'll call it a "static random access memory module with a universal serial bus adapter built in" if you like.
Or I'll keep calling it Super slut drive.