The most rudimentary definition: a top prefers to be in control, often interpreted as preferring to penetrate, while a bottom wants to relinquish some level of control, often interpreted as wanting to be penetrated. Someone who is vers usually finds both positions and power dynamics equally exciting. Of course, this is an oversimplified explanation of an increasingly nuanced framework for sexual preferences

https://www.them.us/story/what-does-it-mean-to-be-a-top-bottom-or-vers