A front line is the closest position(s) of an armed force's personnel and equipment - generally in respect of maritime or land forces. Forward Line of Own Troops (FLOT), or Forward Edge of Battle Area (FEBA) are technical terms used by all branches of the U.S. armed services. They are a battlespace control measure that designate the forward-most friendly maritime or land forces on the battlefield at a given point in time, during an armed conflict. FLOT/FEBA may include covering and screening forces. The Forward Line of Enemy Troops (FLET), is the FEBA from the enemy's perspective.The adjective variant of the term front line is used to describe materiel or personnel intended for forward use - at sea, on land or in the air - i.e. at the front line.In both the naval and land campaigns of World War I, FEBAs, FLOTs and FLETs could often be identified by eye (for example, in France and Belgium, defined by opposing defensive trench systems). Typical current conflicts are vastly different, characterised by 'war amongst the people', the concept of a 'three block war' and the presence of an asymmetric, 360-degree threat from irregular (or extremist/terrorist) combatants. In these cases, the front line, FEBA, FLOT and FLET are almost conceptual ideas; and the term 'front line' has come to refer more to any place where bullets and bombs are flying - or are likely to fly.