what is the equivalent of Windows Active Directory in Linux?

Hey all, sorry for the low level question, but basically I'm looking for the easiest way to set up something like a Windows AD. This would be for something like 10 computers at a local church where I do a lot of their infrastructure work. Is also be interested in sound something similar on my home network, but a while directory is probably overkill. And any suggestions on learnings or other suggestions appreciated!