1 : the relation between a word or phrase and the object or idea it refers to; "he argued that reference is a consequence of conditioned reflexes"
2 : a book to which you can refer for authoritative facts
3 : (computer science) the code that identifies where a piece of information is stored
4 : a formal recommendation by a former employer to a potential future employer describing the person's qualifications and dependability
5 : a remark that calls attention to something or someone