I was recently working on a case and I need a definition of software library. Couldn't find one anywhere. So many of the basics of programming are undefined it makes arguing about programming incredibly difficult -- see every discussion of what a functional language is or strong vs weak typing.
Wikipedia has an article on libraries, which includes the following definition:
"In computer science, a library is a collection of implementations of behavior, written in terms of a language, that has a well-defined interface by which the behavior is invoked."
