/peuhr sen"tuyl, -til/ , Statistics.
n.
1. one of the values of a variable that divides the distribution of the variable into 100 groups having equal frequencies: Ninety percent of the values lie at or below the ninetieth percentile, ten percent above it.
adj.
2. of or pertaining to a percentile or a division of a distribution by percentiles.
[ 1880-85; PERCENT + -ILE ]