ASDF

asdf is a term with multiple meanings in technology and online culture. In everyday typing and keyboard use, asdf refers to the sequence of keys on the left hand home row of a standard QWERTY keyboard (A, S, D, F). It is commonly used as a quick placeholder, a practice sequence in typing tutorials, or a simple way to test input in demonstrations. In online discussions and memes, asdf is often used as a filler or nonce word to convey typing activity or frustration without forming real words.

In programming, ASDF stands for Another System Definition Facility. It is a build and system-management tool for the Common Lisp ecosystem. ASDF provides a standardized way to declare, load, and manage the components of a Lisp software project, handling dependencies and load paths across different Lisp implementations. It has long been the de facto standard for organizing Lisp systems and is commonly used in conjunction with package managers such as Quicklisp. ASDF relies on system description files (often with the .asd extension) to specify how a system should be built and loaded, and it offers commands to load or make systems for development and distribution.

Together, asdf serves both as a practical keyboard reference and as a foundational tool in Lisp development. The term illustrates how a simple keystroke sequence can become part of everyday computing language, while ASDF exemplifies a specialized, widely adopted infrastructure for software building and deployment in a specific programming community.