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.
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.
6. Baseball. A curve ball.
7. Slang. A trick or deception.