The western section of the Roman Empire, first set apart in A.D. 286 by Emperor Diocletian and later (395) formalized after the death of Theodosius I. It comprised Italy, Spain, Gaul, Britain, Illyricum, and northern Africa and lasted until 476.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.
