ice giant
/ˌʌɪs ˈdʒʌɪənt/noun
1 Scandinavian Mythol. = frost giant.
2 Astronomy. A giant planet, such as Uranus and Neptune, whose interior is thought to contain a significant proportion of water, methane, and other normally volatile compounds in condensed forms.
Origin
Mid 19th century; earliest use found in Encyclopedia Americana. From ice + giant.