Pronunciation: (sOO"pur-im-pōz'), [key]
—v.t., -posed, -pos•ing.
1. to impose, place, or set over, above, or on something else.
2. to put or join as an addition (usually fol. by on or upon).
3. Motion Pictures, Television.to print (an image) over another image so that both are seen at once: The credits were superimposed over the opening scene.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.