concatenate two or more lists
Major Section:  PROGRAMMING

Append, which takes two or more arguments, expects all the arguments except perhaps the last to be true (null-terminated) lists. It returns the result of concatenating all the elements of all the given lists into a single list. Actually, in ACL2 append is a macro that expands into calls of the binary function binary-append.

Append is a Common Lisp function. See any Common Lisp documentation for more information.