Barre chords mean that you can easily play any chord using just one 'shape'. Watch the video to learn about them and how to play them. Barre chords help make many songs simple to play, but are usually quite hard to do until you really practice and get used to them. One good thing about them is that you don't have to keep making drastic finger changes to move between different chords - you can just move the whole barre chord up and down the neck to the right positions.
Powerchords are the easiest chords to play on guitar, and are a 'must know'. Later in this section (and the next) we'll explore them a lot more.