A is for Atomic bombs, the most powerful weapon on mid-20th century Earth and the forerunner to the thermonuclear devices that would pose a threat to humanity for the next hundred years.
B is for Bussard Collectors. Set on the forward end of the nacelle, they were designed primarily to collect hydrogen particles for fuel replenishment.
C is for the Canopus Planet, where the famed writer Tarbolde penned "Nightingale Woman" in the year 1996.
D is for Deuterium. The 'matter' in the matter-antimatter reaction and feul in the impulse engines. Easily acquired by separating from seawater. Not drilled or mined as depicted on Enterprise.
E is for eels, Ceti eels specifically. A very hardy organism that you would want to seriously avoid coming into close contact with.
F is for Forward Phaser Bank. The only one we saw used during TOS.
G is for Gary Mitchell, James Kirk's best friend from their mutual Academy days in 2250 until the tragic events at Delta Vega fifteen years later.
H is for Hernandez, Erika. Captain of the NX-02 Columbia.
I is for Isolinear technology, which drove the primary onboard computer systems of Federation starships starting around 2329 and succeeded the duotronic systems in use during the previous eighty-plus years.
J is for Julian Bashir. Genius Doctor. Part-time spy. Passionate lover. Well, I guess two out of three is better than nothing.
K is for Klingon D7 battle cruisers, the most powerful and formidable Klingon warships of the mid-23rd century.