A is for the Altair sector.
B is for the Bussard Collectors. Not "Buzzard". Silly Data.
C is for Cardassia Prime, central planet and homeworld of the Cardassian Empire/Union.
D is for the D. The USS Enterprise 1701-D. Perfected the planetary "belly-flop" manuever.
E is for Enterprise chief engineers, including Trip, Scotty and Geordi.