What exactly is a two-shot? Can there be different types of two shots?

The definitions that I could find of a two-shot are somewhat vague. "a shot that depicts two subjects in the same frame" doesn't really do much justice.

Because there are close-ups that include two subjects in the same frame as well as long shots, medium shots, and medium-close-ups. I'm trying to create a dataset for cinematic shot classification. But this is a problem that I come across very often. I'm unsure whether to label certain frames just as two shots or as medium, MCU, or CUs (depending on the frame). Any Suggestions, please?