the English royal family that reigned 1399–1461, descended from John of Gaunt (Duke of Lancaster), and that included Henry IV, Henry V, and Henry VI. Compare York(def. 1).
Lan·cas·ter 1 (lāng'kə-stər, lān'-) English royal house that from 1399 to 1461 produced three kings of England—Henry IV, Henry V, and Henry VI. During the Wars of the Roses its symbol was a red rose. Lan·cas'tri·an (lāng-kās'trē-ən) adj. & n.
Lan·cas·ter 2 (lāng'kə-stər, -kās'tər, lān'-)
A municipal borough of northwest England north of Liverpool. Chartered in 1193, it was built on the site of a Roman frontier station. Population: 45,900.
An unincorporated community of southern California northeast of Los Angeles. It is a trade center for an irrigated farming area. Population: 141,000.
A city of south-central Ohio southeast of Columbus. The birthplace of William Tecumseh Sherman has been preserved. Population: 36,500.
A city of southeast Pennsylvania west of Philadelphia. A trade center in a rich farming region, it was settled by German Mennonites c. 1709 and was the meeting place of the Continental Congress in 1777. Population: 54,800.
[lang-kuh-ster; for 4–8 also lang-kas-ter] 
kə