I like having a clear definition like basing it on continental plates, though a map of the plates seems to raise its own set of questions. How small is too small of a plate to count? What of parts of what we call continents that are actually on a different plate?

https://upload.wikimedia.org/wikipedia/commons/b/b4/Plate_te...

I think continent, in the general usage, is really more of a cultural/political definition than an an objective standalone concept.