Any one know musical definitions?

had a little band argument yesturday. we were arguing about what a "bridge" is , and what a "pre-chorus" is in terms of songs. any one give good examples in popular songs? i always thought a bridge was a peice of music that was only played once and was different from the chorus and verse. an example i can think of off hand is from the tragically hip song "fiddlers green" . it the part about 3/4 way through and the lyrics are "Nothing changes anyway/anytime"