A piano chord is a group of notes played together to create harmony. The most basic type of chord is the triad, which consists of three notes: the root, the third, and the fifth. For example, a C major chord includes the notes C, E, and G. Chords can be played in various ways, including different inversions and voicings, to produce unique sounds. Chords are essential in music as they provide the foundation for melodies and support the overall structure of a piece. Musicians often use chord progressions, which are sequences of chords, to create movement and emotion in their compositions. Understanding chords is crucial for playing and composing music on the piano.