Cadence: the rate at which you turn the pedals on your bike, in rotations per minute.
I was under the impression that my cadence was quite quick at around 70-80... but thankfully my uber-cycling friend Hank straightened me out.
After a bit of googling, I found this fantastic article.
Bottom line: Most training and all racing should be done at a cadence of 88-95 rpm.
I'm going to really focus on this, as this seems to be one of the big keys to speed, especially when it comes to sustained speed over a long distance. Hopefully I can get from 32km/h over 25k to the mid-30's, and be able to push over 30km/h on longer rides.