Collins COBUILD Advanced Learner's English Dictionary - front line

also front-line (front lines) 1. The front line is the place where two opposing armies are facing each other and where fighting is going on. ...a massive concentration of soldiers on the front line. N-COUNT: usu the N 2. A front line state shares a border with a country that it is at war with or is in conflict with. ...the front-line states bordering South Africa. ADJ: ADJ n 3. Someone who is in the front line has to play a very important part in defending or achieving something. Information officers are in the front line of putting across government policies. PHRASE: v-link PHR, PHR after v