Anhedral describes which wing or tail geometry?

• A. An upward bend from root to tip of wing.
• B. A dihedral angle above the wing.
• C. A flat, level wing with no dihedral.
• D. A downward slant from root to tip of an aircraft's wing or horizontal tail surface.

Answer: (D)

Anhedral is a downward slant of the wing or horizontal stabilizer from the root to the tip, so the tips are lower than the root. This orientation reduces lateral (roll) stability and can increase maneuverability or compensate for other design factors, which is why some aircraft use it.

The other descriptions describe different geometries: an upward bend from root to tip is dihedral, which increases lateral stability; a flat wing has no dihedral; and saying the wing or tail has a downward slant with the angle described as dihedral would actually refer to anhedral only if the angle causes tips to drop. So the downward slant from root to tip matches anhedral.