BADLOW is a coloquial term and not good general term to replace Tanker. Basically we already have an actual word for the aircraft used to fire fires, it just doesn't make sense to replace it with slang acronym.
There are two actual words which can be used to describe vehicles which transport water to the scene for Firefighting apparatus to use: Tanker and Tender.
Tanker is already taken. The term "tender" is used in many realms to mean any vehicle used to support equipment used to actually execute a mission. So in railroading a tender is the "coal car" behind the locomotive, a fuel tender is a vehicle used to supply fuel to working equipment and vehicles. There are in fact different kinds of tenders in NIMS as well:
Fuel Tender: Any vehicle capable of supplying fuel to ground or airborne equipment.
Foam Tender: The apparatus used to mix concentrate with water to make solution, pump, and mix air and solution to make foam, and transport and apply foam.
Helicopter Tender: A ground service vehicle capable of supplying fuel and support equipment to helicopters.
Water Tender: A truck with a permanently mounted water tank with the capabilities of dispensing potable or nonpotable water. The dispensing is handled through gravity or pumped. For pumping action, the truck's engine or transmission is usually used to generate the requirement dispensing energy. Uses can range from delivering potable water to shelter locations, nonpotable form for irrigation, assisting in wildfire situations, dust control, compaction requirements, flushing of storm conveyance sanitary sewer lines, and washing areas of dirt, debris, and dust.
I guess the bottom line question is: What are you doing to get the NIMS definitions changed? I hope more than just skulking around FFN and belly-aching about poeple using the term "Tender" for a water truck.
Like we used to say when I was in the Army, "When you wear a camouflage tuxedo, you dance where they tell you." I personally prefer the term Tanker, but if the people far above my pay grade have decided we have to call them Tenders, then so be it. Years ago, some FF's didn't like to have to wear an airpack, now it's standard practice. We have to learn to keep up with the times or risk being left behind. Stay safe people!