The term Frame was introduced in Minsky's paper ``A Framework for Representing Knowledge''.[MIT AI Memo 306, 1974; reprinted in Brachman, R. and Levesque, H., Readings in Knowledge Representation, Morgan Kaufmann, 1985. Also see Minsky, Marvin, The Society of Mind, Simon & Schuster, 1986.]
A basic idea of frames is that people make use of stereotyped information about typical features of objects, images, and situations; such information is assumed to be structured in large units representing the stereotypes, and these units are what are referred to as ``frames''.
Frames (or something similar) are important because they allow deep understanding of new situations about which only minimal information is directly available. They represent our understanding of regularities in the universe that allow intelligent action based on minimal clues.