* Inlet Hose: This hose carries hot coolant *to* the heater core. It's usually the hotter of the two hoses when the heater is on.
* Outlet Hose: This hose carries cooled coolant *away* from the heater core. It will generally be cooler to the touch than the inlet hose when the heater is on.
You'll find these hoses connected to the heater core itself, usually located behind the dashboard. There's no special naming convention beyond their function.
