drain hose 
Flexible tube through which the washer pump expels wastewater to the standpipe.
house drain 
Pipe using gravity to move the wastewater from the washer to the drain.
standpipe 
Pipe through which wastewater is discharged and carried to the building sewer.
tee 
Shaped like a T, it joins three pipes, one of which is perpendicular to the other two.
air chamber 
Prevents banging in the pipes (water hammer) caused by pressure when a faucet is shut off.