The gaps in the asteroid belt caused by orbital resonances with Jupiter are called Kirkwood gaps.
Astronomer Daniel Kirkwood identified these gaps in 1866 while studying the distribution of asteroid orbital periods and distances from the Sun. They occur where an asteroid's orbital period forms a simple ratio with Jupiter's—for example, the 3:1 resonance, where an asteroid completes three orbits for every one of Jupiter's.
Jupiter's powerful gravity repeatedly perturbs asteroids in these resonant orbits, gradually increasing their orbital eccentricity and often sending them onto planet-crossing paths or out of the main belt. The gaps are therefore regions with unusually few asteroids, not completely empty bands in space: elliptical orbits can still cross them. The Oort cloud is a distant comet reservoir, Trojan asteroids share a planet's orbit, and Lagrange points are gravitationally balanced locations.