1. a. A line that deviates from straightness in a smooth, continuous fashion.
b. A surface that deviates from planarity in a smooth, continuous fashion.
c. Something characterized by such a line or surface, especially a rounded line or contour of the human body.
2. A relatively smooth bend in a road or other course.
3. a. A line representing data on a graph.
b. A trend derived from or as if from such a graph: “Once again, the politicians are behind the curve” (Ted Kennedy).
4. A graphic representation showing the relative performance of individuals as measured against each other, used especially as a method of grading students in which the assignment of grades is based on predetermined proportions of students.
5. Mathematics.
a. The graph of a function on a coordinate plane.
b. The intersection of two surfaces in three dimensions.
c. The graph of the solutions to any equation of two variables.
6. Baseball. A curve ball.
7. Slang. Something that is unexpected or designed to trick or deceive.