a historic region of NW Germany, now mostly in the state of North Rhine-Westphalia
German name: Westfalen
Westphalia in American English
(wɛstˈfeɪliə; wɛstˈfeɪljə)
region in NW Germany, a part of the state of North Rhine-Westphalia: formerly a duchy, a kingdom, and a province of Prussia (1816-1945); chief city, Münster: site, along with Osnabrück, of treaties (Peace of Westphalia) signed in 1648 that ended the Thirty Years' War