The downward angle of a wing in relation to a horizontal cross-section line; aka CATHEDRAL. See DIHEDRAL.
Where the wings are set an angle such that the tips are lower than the centre The opposite of DIHEDRAL 
The angle between an aerofoil and the horizontal when the wing is inclined downwards from its mounting
Downward curve of a bird's wing in flight. ie. Turkey Vulture.
Descriptive of a mineral with no crystal form developed.
The downward angle of a wing in relation to a horizontal cross-section line; aka CATHEDRAL. See DIHEDRAL.
xenomorphic (def. 1).