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1969, American English, shortening of liberation, used with possessives, originally in Women's Lib. Colloquial shortening libber for liberationist is attested from 1971.
Library. In Unix, the directories /lib and /usr/lib traditionally contain files with filename extension ".lib" that are special archives containing modules of standard object code. In modern Unixes the same directories contain ".so" (shared object) files, which are similar except that the object code they contain is designed to be loaded once and shared by all application code that needs it, thus saving memory.