A neck-thru guitar is one in which the neck extends through the body, effectively making the guitar one piece. It is said that neck-thru guitars generally have more resonance and sustain than bolt-ons.
Preamps are generally EQs that allow active shaping of tone and sound before the signal is amplified. Active basses usually have built in preamps, which is what makes them active. In passive basses, there is usually a tone nob (one total or one per pickup) that allows you to cut treble to have a "bassier" tone. With a preamp, you can cut and boost bass, mids and treble depending on the model of preamp.
What else specifically do you want to know? One could write a book on all sorts of bass terms, anatomy and accessories.
