Pronunciation: (kwôr'tīl, -til),[key] —n. 1. Statistics.(in a frequency distribution) one of the values of a variable that divides the distribution of the variable into four groups having equal frequencies. Cf. first quartile, median, third quartile. 2. Astrol.a quartile aspect.
—adj. Astrol.of or pertaining to the aspect of two heavenly bodies when their longitudes differ by 90°.