Overlay may refer to: Computers Overlay network, a computer network which is built on top of another network Hardware overlay, one type of video overlay that uses memory dedicated to the application Another term for exec, replacing one process by another Overlay (programming), a technique to reduce the amount of memory used by a program Overlay keyboard, a specialized keyboard with no pre-set keys Keyboard overlay, a sheet of printed text sitting between the keys, depicting an alternate keyboard layout Vector overlay, an analysis procedure in a geographic information system for integrating multiple data sets Other uses Overlay architecture, temporary elements that supplement existing buildings and infrastructure for major sporting events or festivals Overlay control, in semiconductor manufacturing, for monitoring layer-to-layer alignment on multi-layer device structures Overlay plan, a method of introducing new area codes in telephony Historic overlay district, a zoning district that applies special rules to a portion of other districts, usually for historic or conservation reasons Video overlay, techniques to display video on computer display When the payoffs in gambling are greater than the costs; see Advantage gambling See also Layover (disambiguation) Over (disambiguation) Lay (disambiguation) Overlap (disambiguation) Overload (disambiguation) Superposition (disambiguation)