A decile is one of the nine quantiles that divide an ordered dataset or a probability distribution
into ten equal parts. The 
th
decile is the quantile of order 
for 
.
Thus the fifth decile is a median.
Decile
See also
Decade, Median, Percentile, Quantile, QuartileExplore with Wolfram|Alpha
References
Moore, D. S. and McCabe, G. P. Introduction to the Practice of Statistics, 4th ed. New York: W. H. Freeman, 2002.Cite this as:
Weisstein, Eric W. "Decile." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Decile.html