- One of the four sections made by dividing an area with two perpendicular lines.
- (mathematics) The four regions of the Cartesian plane bounded by the x-axis and y-axis.
- (geometry) One fourth of a circle or disc; a sector with an angle of 90°.
- (nautical) A measuring device with a graduated arc of 90° used in locating an altitude.
noun (plural quartiles)
- (statistics) Any of the three points that divide an ordered distribution into four parts, each containing a quarter of the population.
- (statistics) Any one of the four groups so divided.
- This school is ranked in the first quartile.