Compatibility, when used in a computer or information technology discussions, refers to the ability of one thing to communicate with or interoperate with something else. Two computers are said to be compatible if they are the same maker and model and use the same type of operating system and files. Systems can also be compatible if they are using software that converts their information to a common standard.
For example, you have probably heard the term "IBM-compatible PCs". IBM made the first personal computers (PCs) and everyone else who makes PC-compatible computers builds them so that they can communicate with and exchange data with other IBM-compatible PCs.
Apple computers were incompatible with IBM computers for decades, until Apple released OS X which supports the capability of generating IBM-compatible files.
Frequently, whether or not computer products are compatible depends upon whethery those products comply with a current standard.