quar·tile (kwôrtīl′, -tĭl)
1. Any of the groups that result when a frequency distribution is divided into four groups of equal size.
2. Any of the values that separate each of these groups.
[Middle English, 90 degrees apart (of the relative position of two celestial bodies), from Old French quartil, from Medieval Latin quārtīlis, of a quartile, from Latin quārtus, fourth; see QUART.]
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