In geometry, a straight line joining any two points on a curve. The chord that passes through the centre of a circle (its longest chord) is the diameter. The longest and shortest chords of an ellipse (a regular oval) are called the major and minor axes, respectively.
The number of stripes changed frequently until around 1800. Red, white, and blue became the colours of liberty and an inspiration for other revolutionary flags around the world. Effective date: 19 February 1937.