region of eastern France, from Medieval Latin Lotharingia (German Lothringen), literally "Lothar's Realm." The name is given to what originally was a part of the lands assigned to Lothair I in the first division of the Carolingian empire at the Treaty of Verdun (843 C.E.). Before his death (855 C.E.), Lothair subdivided his lands among his three sons. His son Lothair II (835-869) was given the middle region, subsequently known as Lotharingia. For the name, see Lothario. Related: Lotharingian.

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Definitions of Lorraine from WordNet

Lorraine (n.)
an eastern French region rich in iron-ore deposits;
Synonyms: Lothringen