But then you have newspaper comics - some of which are things like Prince Valiant which are just comic books over time, and then there are the "one joke per day" comics which sometimes have multiple panels, sometimes not.
As with many things, trying to tie it down often reveals that it's not really possible - various "string of one-off" comics (even including The Far Side), political cartoons, etc end up having "recurring characters" that end up with a mythos.
For most people, "digital Far Side" would be a webcomic, because it's something that would live on the comics page in the newspaper.