A is for Asseton Assimilators.
B is for Beltane IX.
C is for Cardassian Armor.
D is for Denebians.
E is for the energy barrier that marks the edge of our galaxy. Encountering it can be a shocking experience.
F is for Frank, young Jim Kirk's uncle. In at least one timeline he was a rude jerk.
G is for Gorn, or Garak, whichever wasn't cited before. If both were cited, then is for Genghis Khan, who killed Surak.
H is for Hirogen subspace relay outposts spread throughout sections of both the Delta and Beta Quadrants.
I is for Interspace.
J is for the Jenolen's transporter buffer.
K is for Klingon bastards.
L is for Lal, the android daughter of Data whose existence was cut tragically short.
M is for M-Class, of which almos all planets in the galaxy are of. OR Matt Jeffries
N is for Nanotechnology. The Denobulans were considered to be proficient at it long before humans.
O is for Organian Peace Treaty.