Crescent wing

The crescent wing is a fixed-wing aircraft configuration in which a swept wing has greater sweep on the inboard section, giving each wing a crescent shape.

As an aircraft enters the transonic region close to the speed of sound, airflow over specific parts can exceed the local critical Mach number and create supersonic shock waves, greatly increasing drag. A swept wing delays the onset of this problem by increasing the critical Mach number. The problem is most severe at the wing root, so increasing the sweep here can further delay the onset and achieve a constant critical Mach number across the whole span.