Chords are named after the root note with the root in uppercase, followed optionally by a sharp(#) or flat(b) symbol. A chord without any other letters or numbers after it is always a major form of that chord: e.g. C (C major), D (D major), A# (A sharp major) or Bb (B flat major), C# (C sharp major) or Db (D flat major).
A chord with a lower case 'm' after the root is a minor form of that chord (eg. Am, Bm, Cm, Dm, Em, Fm, A#m, Dbm). There are many advanced chord forms like G7 (G dominant 7th), Gaug (G augmented triad), Adim7 (A diminished seventh) and so on. See our guitar chord database for more examples.
How are chords constructed? The most basic chord for instance is a major chord (major triad) which is any combination of the first, third and fifth notes of the major scale. For example, a C major chord is made up of any combination of C, E and G (1, 3 and 5 from the C major scale). The first note in the scale is also referred to as the root and will be the name of the chord.
The beauty of the guitar is that it may seem complicated at first, but if you learn a few easy "cowboy chords" you can play with them most rock songs ever written. If you don't know these chords, you can't call yourself a guitar player:
Once you can play each chord correctly, it's time to practice changing from one chord to another. You must be able to change to another chord without stopping.
After getting familiar with guitar chords, you can learn guitar tablature, or sheet music, that will show you the melody line of the song, the chords, and sometimes the base progression.