(Norsemythology) An instance of a type of giants associated with coldness and iciness.
1832, Francis Lieber, Edward Wigglesworth, and Thomas Gamaliel Bradford, editor, Encyclopædia Americana; A Popular Dictionary of Arts, Sciences, Literature, History, Politics, and Biography, volume 9, Philadelphia: Carey and Lea, page 317:
The drops became living by the power of him who had sent the wind ; and from them sprang Ymir, the ice-giant.
1879, “The Deluge: Its Tradition in Ancient Nations”, in The Contemporary Review, volume 36, London: Strahan and Company Limited, translation of Le déluge et l'épopée babylonnienne by François Lenormant, page 484:
The three sons of Borr, Othin, Wili, and We, grandsons of Buri, the first man, slay Ymir, the father of the Hrimthursar or Ice giants, and his body serves them for the construction of the world.
(astronomy) A giant planet composed mostly of astronomical ices (condensed forms of volatile compounds) including water, methane, oxygen, carbon, nitrogen, and sulfur, and smaller than a gas giant. (e.g. Neptune and Uranus)