Also found in: Acronyms, Wikipedia.
A branch of the Celtic languages comprising those spoken or having originated in the British Isles and divided into the Goidelic and Brittonic groups.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.