high level, a vm is an entire virtual machine with its own kernel/operating system/filesystem/etc. a container is a process (and associated files/archived filesystem) with a (more or less) isolated view of the world (network/filesystem/etc.) running on top of the same kernel/os as other processes on the same machine.
examples:
a) vm - an entire windows install running in a window on my linux workstation so i can use tax software once a year. two kernels running at the same time. (N+1 for N VMs)
b) container - a small python service, its dependencies, and various filesystem bits from alpine-minimal packaged into a file that docker/containerd/whatever can turn into the service running in a little isolated portion of my machine. no matter how many i run, one kernel. the various processes just don't see the host or other procs' files/memory/etc. via namespace trickery (unless there's a security problem, lol)
examples: a) vm - an entire windows install running in a window on my linux workstation so i can use tax software once a year. two kernels running at the same time. (N+1 for N VMs) b) container - a small python service, its dependencies, and various filesystem bits from alpine-minimal packaged into a file that docker/containerd/whatever can turn into the service running in a little isolated portion of my machine. no matter how many i run, one kernel. the various processes just don't see the host or other procs' files/memory/etc. via namespace trickery (unless there's a security problem, lol)