Technical issues of separation in function cells and value cells (1988)

> It seems that the designers of Lisp 1.5 thought of function names as being different from variable names--the Lisp 1.5 interpreter looked at the property list of the named atomic symbol first, and so it can be argued that a function was considered a property of a symbol. The designers used the terminology that a symbol "stands for" a function while a variable "refers" to a value.