(large planet made largely of gas)
A gas giant is a giant planet such as Jupiter or Saturn:
massive and mostly gas, i.e., hydrogen and helium.
Many discovered extra-solar planets are gas giants which
is to be expected because larger planets are easier to detect.
GJ 1214 b
Gemini Planet Imager (GPI)
hot Jupiter (HJ)
Keck Planet Imager and Characterizer (KPIC)