front line

noun5

1. •
   A front, or a boundary between opposing positions.
2. •
   A site of a conflict, effort, or controversial matter of any kind.

   • With such results possible on the front line of teaching, the only question remaining is whether much of the education industry will overcome its .... — 2004
3. •
   The site of interaction with outsiders, such as customers.

   • As one front line worker expressed it in a focus group, good managers "have a way about them" that makes them credible to others. ... — 1990
4. •
   attack, collectively the attackers or forwards.
5. •
   A low level.

   • Each of us, from top brass down to the front line worker, wishes to feel the satisfaction of doing something worth while and doing it well. — 1949