Line segment that joins two points of an arc.
- Segment FG in the illustration is a chord.
Segment AD is also a chord. It is the longest chord in the circle. It is called a diameter.
- Chord AB is a chord of this arc of a curve.
- Chord BC is a chord of this parabola.
In a conic section, any chord that passes through the focus is called a focal chord.
In the figure above, chord AB is a focal chord, as it passes through the focus F. The focal chord that is perpendicular to the axis of symmetry of the parabola is called the latus rectum.