The apparent Old Norse cognate form Gautr is a very common byname for Odin.
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The nickname is Gaegol, of which byname indicates Geumgang mountain in North Korea during summer.
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Biscop, while unusual, is not a unique Northumbrian byname.
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In the West, he is commonly known as Tamerlane or Timur Lenk, which derives from his Persian byname.
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Stefano Sciarr-illo byname of Colonna was the name of several members of the Italian family of Colonna.
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The island of Cyprus, one of Astarte's greatest faith centers, supplied the name Cypris as Aphrodite's most common byname.
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He was the Lord of Bouillon, from which he took his byname, from 1076 and the Duke of Lower Lorraine from 1087.
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Writing under the byname Libra, he published many letters in the Manchester Times discussing commercial and economic questions.
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He get this byname becorse he drag the ships from the Baltic across ice and snow to the navigable Russia rivers and in the springtime he sail to attack Constantinople.
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More examples
Nickname: a familiar name for a person (often a shortened version of a person's given name); "Joe's mother would not use his nickname and always called him Joseph"; "Henry's nickname was Slim"
An epithet (from Greek: u1F10u03C0u03AFu03B8u03B5u03C4u03BFu03BD epitheton, neut. of u1F10u03C0u03AFu03B8u03B5u03C4u03BFu03C2 epithetos, "attributed, added") is a sobriquet, or a descriptive term (word or phrase), accompanying or occurring in place of a name and having entered common usage. It can be described as a glorified nickname...
A second name before surnames became fixed and hereditary.