An asteroid belt or asteroid field was the region of a star system that was occupied by asteroids.
The solar system's asteroid belt was located between Mars and Jupiter, formerly the orbit of Planet 5. (TV: Image of the Fendahl) During the Great Breakout of 5000, many frontiersmen and pioneers were concentrated in the asteroid belt while waiting to spread out in the Galaxy. (TV: The Invisible Enemy)
The Aristotle, a hospital ship of the Combined Galactic Resistance, hid from the Daleks within an asteroid belt. (TV: Into the Dalek)
The Hesperus, a salvage ship operated by the Vinvocci, trawled through asteroid fields for junk. (TV: The End of Time)