It's probably too late to change the vernacular. Literally every article on this subject calls it "triple towing."
I'm not going through all the state laws looking for it to actually say "triple." It's always been a waste of time trying to look up the actual legal document where it says that such-and-such is illegal. For example, I can't find ANYTHING on the books in NY that says towing multiple trailers is illegal, yet it reportedly is. It's supposedly illegal to leave your ball hitch in the receiver too, but I can't find the actual law that says so. I can't find the law that says it's illegal to drive over the speed limit. I can't find the law that says it's illegal to drive drunk. I can't find the law that says you need a CDL to tow a trailer over 10,000lbs GVWR.
I do know when you google "is it legal to triple tow in XXX" it sends you to that state's laws on towing.
