anhedral
/anˈhiːdr(ə)l
/adjective Crystallography
(Of a crystal) having no plane faces.The pyroxenoid occurs as granular masses of small anhedral crystals associated with manganoan magnetite....
- Microcline is a common constituent of the intermediate zone, occurring as anhedral crystals to 60 cm.
- Here, olivine (peridot when gemmy) grains or anhedral crystals weather out of basaltic lava.
noun [mass noun] Aeronautics
Downward inclination of an aircraft’s wing. Compare with dihedral.Some gliders have large amounts of anhedral to improve their handling and with this power steering addition the amount of anhedral may be reduced, making the glider more stable to fly and not requiring constant control inputs....
- The five-bladed main rotor is fully composite, with a composite spar, multiple box structure and anhedral tipcaps.
- I've found that hang gliders exhibit a negative coupling between yaw and roll - for example a right yaw will create a left roll - presumably due to anhedral.
Origin
Late 19th century (as an adjective): from an-1 'not' + -hedral (see -hedron).