A jötunn, sometimes anglicized as jotun (pronounced yotun), is a giant in Norse mythology, a member of a race of nature spirits with superhuman strength, described as sometimes standing in opposition to the races of the tribes of the Æsir and Vanir, although they frequently mingle with or intermarry with these. Their otherworldly homeland is Jötunheimr, one of the nine worlds of Norse cosmology, separated from Midgard, the world of humans, by high mountains or dense forests. Other place names are also associated with them, including Niflheimr, Utgarðr and Járnviðr. In some legends and myths they are described as having the same height as humans.
The mountain range of southern Norway is likewise called in Norwegian Jotunheimen or the Jotunheim Mountains.
Jötunn (Proto-Germanic *etunaz) might have the same root as "eat" (Proto-Germanic *etan) and accordingly had the original meaning of "glutton" or "man-eater", possibly in the sense of personifying chaos, the destructive forces of nature. Following the same logic, þurs might be derivative of "thirst" or "blood-thirst." Risi is probably akin to "rise," and so means "towering person" (akin to German Riese, Dutch reus, archaic Swedish rese, giant). The word "jotun" survives in modern Norwegian as giant (though more commonly called trolls), and has evolved into jätte and jætte in modern Swedish and Danish. In modern Icelandic jötunn has kept its original meaning. In Old English, the cognate to jötunn is eoten, whence modern English ettin. Old English also has the cognate þyrs of the same meaning.
A Finnish sea monster and possible god of war was called Tursas which may be related to the word þurs.
The Saami languages, also Finnic, have in their mythology jiettanas, which were man-eating people with several wives. They could be captured and eaten by humans, and their stomachs were filled with gold and silver. Whether or not this word came from Germanic languages is unknown.
Some of the giants are attributed with hideous appearances – claws, fangs, and deformed features, apart from a generally hideous size. Some of them may even have many heads, such as Thrivaldi who had nine of them, or an overall non-humanoid shape; so were Jörmungandr and Fenrir, two of the children of Loki, viewed as giants.
Yet when giants are named and more closely described, they are often given the opposite characteristics. Very old, they carry wisdom from bygone times. It is the giants Mímir and Vafþrúðnir Odin seeks out to gain this pro-cosmic knowledge. Many of the gods' spouses are giants. Njord is married to Skaði, Gerðr becomes the consort of Freyr, Odin gains the love of Gunnlod, and even Thor, the great slayer of their kind, produces a child with Járnsaxa; Magni. As such, they appear as minor gods themselves, which can also be said about the sea giant Ægir, far more connected to the gods than to the other giants occupying Jotunheim. None of these fear light, and in comfort their homes do not differ greatly from those of the gods.