What does ci mean in it industry?

I don't know if the CI you are talking about is continuous integration.

Continuous integration (CI) is a practice, which allows teams to receive feedback and make improvements on a continuous basis, without having to wait until later in the development cycle to find and fix defects. Generally speaking, this means that every time a developer submits a code, all the codes in the library are automatically checked out to an empty directory, and all the test cases are automatically run. If successful, accept this submission, otherwise tell everyone that this is a failed revision.