A basic listing of equipment in Fire/Rescue:
Truck- Can refer to any of many such as a crew truck, an ambulance (also called a bus) Usually it refers to a general purpose unit such as a pumper, or a support vehicle with lighting, tools, etc.
Engine- Usually refers to a pumper truck, though can applie to any used to fight fires.
Pumper- A fire fighting vehicle that has a limited capacity tank for water, a pumping system, hoses and some ladders, and tools.
Tanker- A fire fighting vehicle that can consit of a single unit combined engine and tank, or a towed tank trailer for storage of water.
Ladder- A vehicle that has the primary purpose of carrying a large elevatable ladder for fighting fire/rescue at higher elevations than a small man portable ladder. Some of these units are also equipped with a pumping system, and iether a "cherry picker", or other device with a water cannon.
Rescue- May be iether a small (light) or large (heavy) vehicle with the sole purpose of performing, and supporting rescue/medical operations. These may be equipped with BLS, or ALS equipment/personnel. There are a few combination units that are called Fire/Rescue which combine a pumper with a rescue unit.
Brush- These are very specialized units soley for off road fire fighting, they may be desinged around a 4X4, or a large heavy truck.
Car- Umm duhhh... LOL usually a commanding officer's vehicle.
Squad- A multiple personnel carrying vehicle for carrying a squad or larger unit.
Command- Usually a Mobile Command Unit, which functions as a rolling communications and command center, essentially a rolling fire department.
Ambulance- Again duhhh. An EMS vehicle for the treatment, and transportation of patients to an advanced medical facility. Usually an ALS vehicle with paramedics,.. though some are only fancy BLS rescue units.
Then you have the fun ones that are mission specific, such as foam units, airport units,... and the HazMat units... Hope this helps some.