The more important part of what defines continents is tectonic plates and plate movement, though the definitions used are fairly arbitrary. It's also interesting how different regions in the world define continent in different ways.

The following bit is entirely in humor:

Before the Suez and Panama canals were dug they should have been treated as a single continents? Europe and Asia need to figure out how to dig from the Black Sea to the North Sea so they get some clarity too.

Oh! And while the Evergreen ship was stuck sideways in the Suez, did that make Asia and Africa a single continent for a bit?