A parameter is a number that can be estimated through a statistical procedure. Parameters characterize the distribution of a certain variable under consideration.
For instance, the mean and the variance are two parameters that characterize a a certain population. Those two parameters can be estimated using sample information.
The student population at UWF has certain characteristics. The GPA of the UWF student population has a certain distribution (may be normal) that can be characterized by two parameters, the mean and the variance. These two parameters (usually unknown) can be estimated by applying well known formulas to sample information (for instance, a sample of 50 undergraduate freshmen, sophomores, juniors, and seniors).
For more on parameters, follow the concepts
"Univariate data" and "inferential statistics."