An interceptor was a starfighter classification typically applied to starships that sacrificed heavy ordnance payloads, armor, deflector shields, and/or a hyperdrive in favor of pure speed and agility in combat. To compensate for the lack of a hyperdrive, some types of interceptors could dock with an external hyperspace transport ring, allowing rapid interstellar travel through hyperspace. The ones that could do neither of these things were restricted to realspace, and operated in close proximity to a carrier, capital ship, planet, moon, or space station.
Obi-Wan Kenobi's Delta-7 Aethersprite-class light interceptor
Shortly before and during the Clone War, the Jedi Order operated a class of interceptors designated as the Delta-7 Aethersprite-class light interceptor. These starfighters were fast and maneuverable, and equipped with an integral astromech droid for hyperspace jump calculations. Although not equipped with an internal hyperdrive, they could hook up to an external Syliure-31 hyperspace docking ring for superluminous interstellar travel. Obi-Wan Kenobi's personal Delta-7 was also equipped with canisters for spare parts, which could be jettisoned in flight. Kenobi put this feature to good use in the dogfight over Geonosis to evade Jango and Boba Fett.
TIE interceptors during the Battle of Endor
The Galactic Empire's TIE/IN interceptor was developed as a continuation of the TIE Advanced projects, and was deployed as early as 2 years before the Battle of Yavin in crackdowns on rebel activity. Like other TIEs, it lacked a hyperdrive and shielding, but it was heavily armed with no fewer than six laser cannons. The TIE/d "Defender" Multi-Role Starfighter was developed by Grand Admiral Thrawn as an upgraded version, with a third pair of solar panels and shielding.
Although not typically labeled as such, spacecraft as diverse as the Galactic Republic's V-19 Torrent starfighter and the Firespray-31-class patrol and attack craft were also referred to as "interceptors" from time to time. By the time of the Cold War, dedicated interceptors were rarely seen in battle. The Resistance continued to operate a small number of A-wings.
A TIE/ba Baron during the Cold War.
The First Order created their own TIE/ba Baron Space Superiority Interceptor.