The phrase "bell housing" refers to a protective cover that connects the engine and the transmission in a vehicle. It provides support and keeps them in place, allowing them to work properly together and transfer power. Full definition
The wet starting clutch is installed in the clutch bell housing of the 8 - speed automatic transmission instead of the torque converter. (greencarcongress.com)
There should be more than enough support at the transmission bell housing mounting points to support the engine off of the stand. (mechanics.stackexchange.com)