I was looking over material.io and it often mentions continuity within different topics. Though it doesn't give a single definition.
How would you define visual continuity in a few lines?
Here black dots are not of the same size
Here shape is the same and color is different
But both have continuity.
This article will help you to understand more https://www.usertesting.com/blog/gestalt-principles#continuity
It basically means consistency all around across the entire app as having the same feel of touch when interacting with it.
Note: Even it's normally not preferred to present solely a sentence as an answer, I'll keep it enough to be able to provide enough reasoning with the question that represents bringing short description to the used term in this specific situation.