What is "overlap" meaning??

Hi
I see this phrase a lot, like “overlap schools” and I see forums on it sometimes.
Does it just mean schools that are commonly applied to together or schools people go to (like UG then Grad)??

I’m just a bit confused. no real definition for it anywhere

I think overlap schools are ones that have several similarities, so students who apply to one often apply to the other, like Duke & Vanderbilt.

Many of the college guides (and Naviance ) call schools that share applicants “overlaps”.

It is an easy way to identify similar schools if you believe that students apply the same filters in selecting schools. (Most do in terms of geography, size, and general vibe.)