Explanation:

It is a planet that does not orbit Sun and instead orbits different star, stellar remnant, or brown dwarf. It is also termed as extrasolar planet.
The first such planet orbiting star similar to our own Sun was detected only in 1995. Today some 3,600 exoplanets have been found, ranging from rocky Earth-sized planets to large gas giants like Jupiter
Image: Size comparison of Jupiter and the exoplanet TrES-3b. TrES-3b has an orbital period of only 31 hours and is classified as a Hot Jupiter for being large and close to its star, making it one of the easiest planets to detect by the transit method.
Learning: The discovery of exoplanets has intensified interest in the search for extraterrestrial life.
There is special interest in planets that orbit in a star's habitable zone, where it is possible for liquid water, a prerequisite for life on Earth, to exist on the surface.
Besides exoplanets, there are also rogue planets, which do not orbit any star and which tend to be considered separately, especially if they are gas giants