What is meant by a "fast" pre amp


I have heard a pre amp described as "fast", what does that description mean?
brf
Post removed 
Brf, Is the technical definition what you wanted? The last thing you want to do is buy equipment based on specs or some long elaborate explanation. The tweak industry is full of this kind of talk with space age materials and methods that only a NASA engineer would know.
The real question is; Does it sound like music?
Buying on specs only leads to disappointment.
BRF
............Are you serious?? The guy asked for audio help, not english lessons.