Hi

BB: mean the engine has ball bearings in it. most now days do

Ringed: At the top of the piston there are rings. these rings heat up they expand making a seal between the liner and the pisten.

ABC: Aluminium piston in a chrome plated brass liner. This tapers at the top, so at compression it is very stiff to turn over. as the engine is run the top of the liner expands with the heat.

this is the very basics of an engine topic. I could go further intothe topic, but i dont know much more off the top of my head

Hope this helps

Ian