rover
One who roves: a person or animal that travels around, especially over a wide area, without a fixed destination; a nomad, a roamer, a wanderer.
Other meanings
Also rover ticket: a person who has a ticket for an event, performance, etc., but no assigned seat, and so has to find a place to sit or stand.
A small manned or unmanned land vehicle for exploring extraterrestrial bodies.
Word history
From Old Norse "ráfa" (to roam, wander).
Where this comes from
This definition is adapted from “rover” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.