My statistics are relatively weak anymore, so I'll do what I can. Generally speaking, a school's curve refers to either the median or mean grade the school has used to center its grading bell curve. If a school has a 2.87 curve, that means, depending on their mapping of letter grades to point values, they decided that either the mean or median of their student's grades should be between a C+ and B-. A 3.0 means it should be a B. And so on.

These distributions usually vary by the type of class. USF's distributions would seem to indicate a C+/B- curve to me. Many schools use much lower curves, or at the very least less shifted (away from F's) in an effort to weed out their classes.

For a rather exhaustive look at all of this, see Robert C. Downs and Nancy Levit, If It Can't Be Lake Woebegone... a Nationwide Survey of Law School Grading and Grade Normalization Practices, 65 UMKC L. Rev. 819 (1997).