Some more acronyms and jargon:
MUP: Multi-use path. Paths intended for bicycles, pedestrians, runners, rollerbladers, possibly equestrians.
muppet: someone misusing a multi-use path. Can be be used by snobbish road cyclists referring to all cyclists who use MUPs instead of the roads, or to refer someone simply being inconsiderate (wearing headphones, talking on the phone, weaving in and out of the lane(s), riding/walking on the wrong side of the path)
salmon: someone who travels against the flow of traffic (in the US, on the left side of the road). While you may have been taught to ride against traffic, and you should travel against traffic while on foot, it is not very wise to do so on a bike.
fear from the rear: the feeling that you're going to be rear ended if you travel with traffic, leading to salmoning. The fear will go away with experience.
endo: going over the front bars
As for the definition of Fred: That's the wonderful thing about the English language- words can have multiple definitions, depending on context!