"10 x 100 @ 1:30": A set of 10 100's, starting each one on a 1:30 interval.
"S"=Swim, "K"=Kick, "P"=Pull, "D"=Drill
"Shooter": Kick underwater off the wall as hard and long as you can.
"Negative Split": Swim the second half of the given distance faster than the first half.
"Descend": Swim each repetition of the set faster than the previous one.
"Breathe 3 / 5 by 50": For the given distance, swim the first 50 breathing every third stroke (alternate sides), the second 50 breathing every 5th stroke, repeat until done with the distance.

Studs: The "Stud" lanes swim the workouts with the longest yardage and most difficult intervals.
Discount: The "Senior Citizen Discount" lanes swim the workouts with reduced yardage and longer intervals.
Boomers: The "Baby Boomers" lanes swim the workouts whose difficulty is between that of the Stud and Discount Lanes.