A barre chord is a chord where you use your first finger to "bar" the entire fret. The other chords are usually called "open" chords. Btw, if you think barre chords are tough, try learning some of the jazzier chord voicings where you use fingers other than your first to hold down partial barres....carpel tunnel chords...heh
"Terminat Bora Diem, Terminal Auctor opus."