leading edge (of a wing, propeller, etc.)
Technical term in aviation and aerodynamics for the front edge of an airfoil or propeller blade.
It is dangerous when ice accumulates on the leading edge of the wing.
The leading edge of the propeller is the part that first cuts through the air.
forward edge of the battle area
Compound of 前 (front) and 縁 (edge, rim). The reading ぜんえん follows standard on'yomi.