Victor Wooten of the Flecktones is an amazing electric bassist. He has a solo album out (my son has it, can't remember the name) of JUST HIM on bass, and it is truly unbelievable.

I use the following terms interchangeably to mean the same thing:
acoustic bass
upright bass
stand-up bass
bass fiddle
bass violin

These are different from the following:
electric bass
bass guitar
acoustic bass guitar

Electric bass usually means an electric bass guitar with 4 tuners instead of 6 and heavier strings, but there is also an electric upright bass, sort of a broomstick with strings, that's really interesting looking, and played like an acoustic upright bass.

We just had a wonderful session last night with 2 upright basses (not usually recommended), 2 banjos, 4 guitars, 1 mandolin and 1 fiddle. Of course, the banjos won!