Terrestrial planets are mainly composed of while jovian planets are made dominantly of

Jupiter, Saturn, Uranus and Neptune are the jovian planets.
Mercury, Venus and Earth are the terrestrial planets.

One of the main differences that can be seen between terrestrial and jovian planets, is their surfaces. While the terrestrial planets are made of solid surfaces, the jovian planets are made of gaseous surfaces.

The jovian planets are less dense compared to the terrestrial planets, because they are mainly composed of hydrogen gas. Moreover, the core of the jovian planets is more dense than the terrestrial planets.

So, Terrestrial planets are mainly composed of solid surfaces while jovian planets are made dominantly of __gaseous.