A tractor beam is a device that can apply force remotely to other objects. Tractor beams are usually installed on starships and used for towing other starships, although they can be used as weapons if sufficiently powerful.
Tractor beams in Star Trek typically have short range, often less than a kilometer. Tractor beams interfere with transporter function, blocking or even redirecting transporter beams. Tractor beams can also negatively affect the performance of disruptors.
The range of tractor beams in Star Wars is inconsistent. The range of tractor beams on Imperial Star Destroyers (including the Executor) appears to be very short (a few kilometers), but the range of the tractor beam on the Death Star was apparently very long (hundreds or thousands of kilometers).