Definition of drum:
5 : something resembling a drum in shape: such as a (1) : any of the cylindrical blocks that form the shaft of a column (2) : a round wall or structure that supports a dome
b : a cylindrical machine or mechanical device or part
c : a cylindrical container; specifically : a large usually metal container for liquids ·a 55-gallon drum
https://www.merriam-webster.com/dictionary/drum
Tub:
1. a wide, open, deep, typically round container with a flat bottom used for holding liquids, growing plants, etc.
Basket:
1. a container used to hold or carry things, typically made from interwoven strips of cane or wire.
Early wringer, semi-automatic and later fully automatic washers that were top loading, were just that; tubs mounted by various means to hold washing. No different really than the various metal, wood, or porcelain tubs of old used on laundry day. If you want to upmarket things and get away from references to the drudgery of past, there is always "basket" for top loading washers.
H-axis washers obviously have some sort of container to hold laundry, but as they aren't open from top nor derived from stationary wash tubs went with "barrel" or even "wheel" because that is what the things closely resembled both in appearance and action of movement.
Suds container seems to be a rather modern incarnation used for H-axis wash wheels. It *may* be an English translation of something in German since Miele and Bosh (among others) seem to be some of the first to use that term starting around early in this or last decade:
https://patents.google.com/patent/US7640771
