anhedral

This term is a specialized technical descriptor used almost exclusively in aeronautical engineering and aerodynamics. It describes a specific geometric configuration where wings slope downward from the root to the tip, which is the opposite of dihedral. This configuration is typically employed to decrease excessive stability in aircraft that are naturally too stable in the roll axis, thereby improving maneuverability.

Because it is a highly specific technical adjective, it is rarely found outside of aviation manuals, engineering textbooks, or professional discussions regarding aircraft design. It does not have a common metaphorical or casual usage in general English.