In HFS+ and APFS the concepts of partition and container are similar but different in implementation. When you need to segment a disk in HFS+ you use a partition. In APFS it's a container. You can still partition a drive that has an APFS container. This is required for Boot Camp. A partition space isn't able to be shared with other volumes. Container free space is able to be shared among other containers in the system. For most of us that's the big take away.
For those that want to geek out on APFS Apple has this...
https://developer.apple.com/document...le_file_system