Why do we write "abi" before abi.encode()? I understand that ABI is a like a JSON file used to help interaction of different applications because the solidity code is stored as bytecode, but I don't understand why we write "abi" before some "specific" functions in solidity.
I also know that abi.decode is a specific decoding function but why do we add "abi" before it. What is its usecase? https://solidity.readthedocs.io/en/v0.5.3/units-and-global-variables.html#abi-encoding-and-decoding-functions