CRC stands for Class, Responsibilities, and Collaborators.
CRC card is first introduced by Kent Beck and Ward Cunningham to help teach procedural programmers object-oriented design in 1989 in their paper "A Laboratory For Teaching Object-Oriented Thinking".
CRC card is used for identifying the object in a design by its three dimensions: class name, responsibilities, and collaborators, which gives learners a direct experience of objects.
They claimed "this approach successful in teaching novice programmers the concepts of object and in introducing experienced programmers to complicated existing design".