Chords are simply more than one note played at the same time. When played alongside a melody, they provide harmony.
Chords that go well together - Basic Major Key Triads that make up the majority of all other chords.
Chord Spellings - A brief explanation of how and why chords have "spellings" .
Chords are the mainstay of any guitarist. When the instrument was first introduced, it's acoustic volume was so low when compared to other instruments in an ensemble (e.g. Brass or Woodwind), it was rarely thought of as a solo instrument. Instead, it was used for rhythmic accompaniment. Not until the amplification of the guitar did it become seriously considered a solo instrument.