---Definition (informal)---

A description of rules for manipulating data.

---Source---

Abelson, H., Sussman, G. J., & Sussman, J. (1996). Structure and Interpretation of Computer Programs - 2nd Edition (MIT Electrical Engineering and Computer Science) (second edition) [E-book]. The MIT Press.

---Example---

Is it true that this is a procedure? Why?

(defun my-length (list)  
    (if list  
        (1  (my-length (cdr list)))  
        0))  

Yes, because it describes rules for manipulating a given list.

---Template---

Is it true that this is a procedure? Why?

<insert example>

Yes, because it describes rules for manipulating a given "________."

---Notes---

N/A