Also, what's the difference between bass and treble?
I go by approximate frequencies, but sometimes slip into describing specific instruments. For me:
60-160Hz: Mid-bass (80-110 for the mid-bass hump)
160-~1kHz: Lower mid-range
~1kHz-4kHz: Upper mid-range
>10kHz: Upper treble
For instruments, kick drum and bass guitar are usually in the mid-bass, with some of it in the sub-bass with synthetic bass and stuff like that. Lower mid-range has some more bass guitar, guitar that's tuned down, and deep voices. Upper mid-range has higher voices, guitar, and snare drum attack. Treble has cymbal, sibilance, flutes, and synthetic trebly noise stuff.
Aaaand in case OP wants an explanation in terms other than frequencies:
Think of a drum. You know the "oomph" of the kick? Bass.
High hats? Treble.
This is a very rough guide, but I suspect many people do think of bass and treble in such terms.