defsystem system-name options &key members rules
A symbol used as the name of the system. If a string is given, it is interned in the current package.
Any of a number of options that can be specified.
The members of the system. These may be files of Common Lisp source code, foreign source code, or other systems.
A set of rules describing the requirements for and order in which compilation and loading of the system members should take place.
See the following sections for more information about these parameters.
LispWorks User Guide and Reference Manual - 21 Dec 2011