Constituting or belonging to the first, highest, or best group in a system of classification: a first-class hotel; first-class mail.
Of the foremost excellence or highest quality; first-rate: a first-class mind.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.