Guitar Preamp Pedal Guitar Effects? What Do They Mean?

Guitar Effects? What do they mean? - guitar preamp pedal

I am ashamed to ask, but I play the guitar for 7 years and still do not know what many pedals. I'm embarrassed to ask a teenager at the local Guitar Center, so here goes. What is the compressor, envelope filter, noise reduction, Octave, preamplifier and "pedal? What does each do? Thank you.