-Operating-system-level virtualization is a server-virtualization
-method where the kernel of an operating system allows for multiple
-isolated user-space instances, instead of just one. We call such
-instances containers. As containers use the host's kernel they are
-limited to Linux guests.
+In the context of containers, these terms all refer to the concept of
+operating-system-level virtualization. Operating-system-level virtualization is
+a method of virtualization, in which the kernel of an operating system
+allows for multiple isolated instances, that all share the kernel. When
+referring to LXC, we call such instances containers. Because containers use the
+host's kernel rather than emulating a full operating system, they require less
+overhead, but are limited to Linux guests.