A universal library is a library with universal collections. This may be expressed in terms of it containing all existing information, useful information, all books, all works (regardless of format) or even all possible works. This ideal, although unrealizable, has influenced and continues to influence librarians and others and be a goal which is aspired to. Universal libraries are often assumed to have a complete set of useful features (such as finding aids, translation tools, alternative formats, etc.).
Source: Universal library – Wikipedia