ANSI Common Lisp  24 System Construction 24.1 System Construction Concepts
24.1.2 FeaturesA feature is an aspect or attribute of Common Lisp, of the implementation, or of the environment. A feature is identified by a symbol.A feature is said to be present in a Lisp image if and only if the symbol naming it is an element of the list held by the variable *features*, which is called the features list. |