The "middle" of the data set. There are many measures of center.
The understanding of the key features of a set of data - shape, center, spread, and outliers.
Points in a data set that are so high or so low as to be unusual, given the rest of the values.
The qualitative description of the clustering of data points in a certain location when the data are graphed.
The numerical description of how close the numbers are to the center.