ELI5: Explain Like I'm 5

Execution unit

An execution unit is like a little worker inside a computer. Its job is to do things that the computer tells it to do, like adding numbers together or moving information from one place to another. The execution unit has its own special language that it understands and uses to communicate with the rest of the computer. When the computer wants something to be done, it sends a message to the execution unit in its language, and the execution unit figures out what needs to be done and does it. Sometimes the execution unit has to ask for more information or help from other workers in the computer, but it always does its best to get the job done right.