Unix has process groups.

Unix has access control (ie. memory protection, FS access protection, FS root aka chroot).

Containers are process groups with access control.

The actual entity has a different name pretty much everywhere, eg. Solaris Zone, Linux namespace and Linux cgroups. Usually the OS throws in a wider bunch of stuff that is only loosely related to access control in the classic sense, eg. CPU and memory limiting, I/O rate limiting and such (so rusage access control, in a sense).