According to Wikipedia, a Chord in music is any harmonic set of pitches consisting of two or more notes that are played together simultaneously. In guitar, a chord is a melodious sound produced by a group of different strings that are held together for the production of a certain key or note. Chords in music are widely used in the Eastern and Western African and in Western classical music. The use of chords in music is absent in many other parts of the world.
In guitar, there are different chords that are played according to music. There are both major, minor and other chords found in the guitar. It all depends on what kind of music played.
There are seven major chords in the guitar as displayed in the chart below.