1 files changed, 13 insertions, 2 deletions

diff --git a/lisp/emacs-lisp/cl-preloaded.el b/lisp/emacs-lisp/cl-preloaded.el
index 83d9e6ee220..fa745396b02 100644
--- a/lisp/emacs-lisp/cl-preloaded.el
+++ b/lisp/emacs-lisp/cl-preloaded.el
@@ -444,13 +444,24 @@ For this build of Emacs it's %dbit."
   )
 (cl--define-built-in-type compiled-function (function)
   "Abstract type of functions that have been compiled.")
-(cl--define-built-in-type byte-code-function (compiled-function)
+(cl--define-built-in-type closure (function)
+  "Abstract type of functions represented by a vector-like object.
+You can access the object's internals with `aref'.
+The fields are used as follows:
+
+  0 [args]       Argument list (either a list or an integer)
+  1 [code]       Either a byte-code string or a list of Lisp forms
+  2 [constants]  Either vector of constants or a lexical environment
+  3 [stackdepth] Maximum amount of stack depth used by the byte-code
+  4 [docstring]  The documentation, or a reference to it
+  5 [iform]      The interactive form (if present)")
+(cl--define-built-in-type byte-code-function (compiled-function closure)
   "Type of functions that have been byte-compiled.")
 (cl--define-built-in-type subr (atom)
   "Abstract type of functions compiled to machine code.")
 (cl--define-built-in-type module-function (function)
   "Type of functions provided via the module API.")
-(cl--define-built-in-type interpreted-function (function)
+(cl--define-built-in-type interpreted-function (closure)
   "Type of functions that have not been compiled.")
 (cl--define-built-in-type special-form (subr)
   "Type of the core syntactic elements of the Emacs Lisp language.")