'Jovian' may mean (1) of or relating to the planet Jupiter, or (2) any Jupiter-like (large gas giant) planet.
The fact that the majority of exoplanets found to date are Jovians in small orbits is a selection effect, resulting from the fact that these objects exert a relatively large gravitational pull on their host stars and are therefore the easiest to detect. Numerous Earth-class planets are expected to be found in the future through the use of more sensitive equipment, both on the ground and in space. Theory suggests that large jovians, with masses several times that of Jupiter, should tend to occur around stars having a high abundance of elements heavier than hydrogen and helium. Such elements, in the protoplanetary disk, form dust particles and then, by agglomeration, planetesimals and the rock-metal cores of gas giants.