LISP routine

Short answer

A self-contained AutoLISP program that adds a command or behaviour to AutoCAD — usually one .lsp/.fas file.

'LISP routine' is the everyday name CAD pros use for a single, packaged AutoLISP utility. It's typically one .lsp or .fas file that defines one or more (defun C:CMDNAME …) functions — the C: prefix makes them callable as AutoCAD commands. A routine might draw a custom rebar callout, batch-rename layers, or export a parts list. Marketplaces like CAD Exchange list thousands of LISP routines because they're the fastest unit of automation to publish and consume.

Related guides

How to Load a LISP Routine in AutoCAD

Three reliable ways to load .lsp, .fas, and .vlx files into AutoCAD, plus how to add them to the Startup Suite so you never reload again.

Browse related listings

AutoCAD LISP Routines

Hundreds of verified AutoLISP and Visual LISP routines for AutoCAD: .lsp source, compiled .fas, and bundled .vlx applications. Loaded with APPLOAD, version-friendly, malware-scanned.

Related terms

LISP

A scripting language used to automate AutoCAD by writing routines that issue commands, query drawings, and build custom tools.

AutoLISP

Autodesk's dialect of LISP, built into AutoCAD since 1986, used to write custom commands and automate drawings.

FAS

A compiled, single-file binary of an AutoLISP/Visual LISP routine. Faster to load and obscures the source code.