What qualifies a substance as a "bath salt"

I've tested 5+ different substance that were supposed to be "MDMA" since having my Marquis reagent test kit. And only one has shown up as real MDMA. So which "research chemicals, RCs" or other substances are classified as bath salts? I know the MDxx's are considered bath salts, but what else is????


**ahead of time, I'm black out drunk right now... so excuse any spelling/ grammar errors

i was under the impression that MDPV was referred to as the infamous "bath salt"

Any RC can be considered a bath salt, but it's pretty much only stimulant RCs. MDPV and 4-MMC are the ones I heard of the most