A programming language created by Robin popplestone in 1975, originally for the PDP-11. pop-11 is stack-oriented, extensible, and efficient like FORTH. It is also functional, dynamically typed, interactive, with garbage collection like LISP, and the syntax is {block structured} like {Pascal}. ["Programming in pop-11", J. Laventhol , Blackwell 1987]. Alphapop is an implementation for the Macintosh from Computable Functions Inc. popTalk and popLOG from the University of Sussex are available for VAX/VMS and most workstations. E-mail: Robin popplestone <pop@cs.umass.edu> (2003-03-25)