composed of regular members, participants, etc. (distinguished from substitute): the first-string team.
foremost; main: the first-string critics.
Origin of first-string
First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the top player of a team in an individual sport, such as squash
being a regular member of a team rather than a substitute or reserve
being the top player of a team in an individual sport
of high rating; first-class
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012