Library file
A library file was an actual executable code that would do the work as specified in a header file.
In 2365, while discussing the Sherlock Holmes holographic story and Holmes' arch-enemy, Professor James Moriarty, that were all made and used by Geordi La Forge, both Captain Jean-Luc Picard and Data found out that he had access to the computer and their library files as well. (TNG: "Elementary, Dear Data")