asdf or ASDF may refer to* asdf, the sequence of letters that appear on the first four keys on the home row on a QWERTY or QWERTZ keyboard Association of Synchronous Data Formats, an organization that advances the use of synchronous data transmission technology Another System Definition Facility, the most commonly used build system for Common Lisp Alabama State Defense Force, a military entity Average Squared Difference Function, a mapping used in pitch detection algorithms Hoverboard ASDF,… (More on Asdf)