The set of all objects. It is a supertype of every type, including itself. Every object is of type t.
Called an empty type since it contains no objects. It is a subtype of every type. No object is of type nil.
Contains the symbols t and nil, which represent true and false, respectively.
A function is an object that represents code to be executed when an appropriate number of arguments is supplied.
typep object type-specifier [environment] ⇒ boolean
subtypep type-1 type-2 [environment] ⇒ subtype-p, valid-p