W,X,Y,Z zenith - The point directly overhead for any observer on the surface of Earth.  The angle between the zenith and the horizon is defined to be ninety degrees.
A A A B B B C C C D D D E E E F F F G G G H H H I,J I,J I,J K K K L L L M M M N N N O O O P,Q P,Q P,Q R R R S S S T T T U,V U,V U,V W,X,Y,Z W,X,Y,Z Numbers Numbers Numbers
Glossary
Carpe Caelum