5 C.F.R. § 511.101 Definitions.
In this part:
(a) Agency and employee have the meanings given them by section 5102 of title 5, United States Code.
(b) Class means all positions which are sufficiently similar as to (1) kind or subject-matter of work, (2) level of difficulty and responsibility, and (3) the qualification requirements of the work, to warrant similar treatment in personnel and pay administration.
(c) Classification means the analysis and identification of a position and placing it in a class under the position-classification plan established by OPM under chapter 51 of title 5, United States Code.
(d) Grade means all classes of positions which (although different with respect to kind or subject-matter of work) are sufficiently equivalent as to (1) level of difficulty and responsibility, and (2) level of qualification requirements of the work, to warrant their inclusion within one range of rates of basic pay.
(e) Position means the work, consisting of the duties and responsibilities, assigned by competent authority for performance by an employee.