The first percentile has 99% of the observations in the ordered set below it.
The first decile is equal to the 90th percentile and has 10% of the observations in the ordered set below it.
The median is equal to the 50th percentile.
The range is the difference between the 1st and 99th percentiles.
The interquartile range lies between the 1st and 3rd quartiles.
Quartiles divide the data set into 100 equally sized groups.