quick question for the pros from a rookie CBU what does that stand for?

[bathroom rookie]

CBU what does that stand for?
I thought it stood for cement board, but the way some of you folks use CBU it has to stand for something else. Please tell me what it means. Thanks

[jimbo]

cement board underlayment

[LLigetfa]

Cementious Backer Unit

http://acronyms.thefreedictionary.co...us+Backer+Unit

[jadnashua]

IE, a decoupling layer designed to be compatible with a tile installation. With few exceptions, I prefer newer, alternative materials (sheet membranes, whether user applied or in board format from the factory). Faster, neater, lighter to install. Actually waterPROOF, rather than water resistant (and stable).