- available for immediate service, especially combat service: first-line troops.
- of prime importance or quality.
Origin of first-line
First recorded in 1895–1900
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for first-line
In the first-line trenches they could see no one and felt uncertain what to do.The Birth of Yugoslavia, Volume 1
Her cottage, which was less than a mile from our first-line trenches, was partly in ruins.
Sleep is a luxury indulged in but rarely in the first-line trenches.
Was it dream or reality that you were walking about in the first-line German trenches?
He had watched their advance from the first-line British trench.
- acting or used as a first resortfirst-line treatment; first-line batsmen
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