The term integration refers to the ability to?

In computer technology, we have the so called integration term. It is refers to the ability of the computer or program to integrate 2 or more codes into a system. For example, different developers are doing a single project and each one of them are assigned to a different features. Thus this is called, unit coding then if they already finished doing their codes, they will finally integrate it into one big system. And that process that they did is called integration.