Chord symbols are shorthand notations used in music to indicate the chords that should be played in a piece. They typically consist of a letter representing the root note, such as C for C major, followed by additional symbols to indicate the chord quality, like maj for major or min for minor. These symbols help musicians quickly understand the harmonic structure of a song. In addition to basic chords, chord symbols can include numbers and other symbols to denote extensions and alterations. For example, C7 indicates a C major chord with an added minor seventh, while Cmaj7 signifies a C major chord with a major seventh. This system allows for efficient communication among musicians.