Kinktionary
More like guidelines and a lot less like definitions.
Vers
Short for "versatile", this refers to a person who can take on either a Top (giving) or bottom (receiving) role. The degree of preference for one or the other varies - some people who have a strong preference may use terms like vers top or vers bottom to communicate it.
Sometimes also used interchangeably with Switch to mean alternating between dominant and submissive roles.
More broadly, "versatile" can be used to communicate a general openness to exploring new kinks, acts and roles.
As a LGBTQ+ community role
In the LGBTQ+ community, the full term (versatile) is also used to describe being a partner who will give and receive penetration during sex. See Versatile (gay culture).