Simple Definition of front line
: an area where soldiers are fighting
: the most important and active position in a job or field of activity
Full Definition of front line
1 a : a military line formed by the most advanced tactical combat units; also : front 2a(2) b : an area of potential or actual conflict or struggle
2 : the most advanced, responsible, or visible position in a field or activity
Examples of front line in a sentence
These researchers are on the front line of defense against cancer.
She has been working on the front lines to educate the poor.
First Known Use of front line
Learn More about front line
Thesaurus: All synonyms and antonyms for front line
Seen and Heard
What made you want to look up front line? Please tell us where you read or heard it (including the quote, if possible).