In common usage, an interceptor is a fast fightercraft designed to intercept enemy aircraft before they come close enough to friendly surface assets to become a threat.
Interceptors in Star Wars
Interceptors in Babylon 5
In Babylon 5, an interceptor is a defensive weapon, not a starfighter. Widely used by the Earth Alliance, an interceptor is a rapid-fire pulse weapon that can disrupt incoming weapon pulses, destroy fighters and missiles, or reduce the impact of beam weapons.
Interceptors in XCOM
The Interceptor is a type of fighter that is utilized by XCOM until the development of the firestorm. It mounts several nuclear missiles. The interceptor has a maximum speed of 2,100 Knots (Mach 3.17) and a range of 8,050 nautical miles. It also has a cost of 600,000 USD.