A chord in the context of strings refers to a segment that connects two points on a curve or a circle. In geometry, it is a straight line that joins two points on the circumference of a circle, and it can also be defined in relation to other shapes. Chords can vary in length, with the longest chord being the diameter of the circle. In music, a chord is a combination of three or more notes played simultaneously. Chords form the foundation of harmony in music, providing a rich sound that supports melodies. Common types of chords include major, minor, and diminished, each creating different emotional effects in compositions.