This chapter describes the LispWorks extensions to symbols in the
package, which is used by default. This chapter notes only those differences between LispWorks and the ANSI Common Lisp standard. You should refer to this standard (an HTML version, the Common Lisp Hyperspec, is supplied with LispWorks) for full documentation about standard Common Lisp symbols.
LispWorks User Guide and Reference Manual - 21 Dec 2011