1. [n]  protective covering consisting, for example, of a layer of boards applied to the studs and joists of a building to strengthen it and serve as a foundation for a weatherproof exterior
2. [v]  kill by lying on; "The sow overlay her piglets"
3. [v]  put something on top of something else; "cover the meat with a lot of gravy"

Overlay
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1. \O`ver*lay"\, v. t. [imp. & p. p. {Overlaid}; p. pr. &
   vb. n. {Overlaying}.]
   1. To lay, or spread, something over or across; hence, to
      cover; to overwhelm; to press excessively upon.
            When any country is overlaid by the multitude which
            live upon it.                         --Sir W.
                                                  Raleigh.
            As when a cloud his beams doth overlay. --Spenser.
            Framed of cedar overlaid with gold.   --Milton.
            And overlay With this portentous bridge the dark
            abyss.                                --Milton.
   2. To smother with a close covering, or by lying upon.
            This woman's child died in the night; because she
            overlaid it.                          --1 Kings iii.
                                                  19.
            A heap of ashes that o'erlays your fire. --Dryden.
   3. (Printing) To put an overlay on.
   

2. \O"ver*lay`\, n.
   1. A covering. --Sir W. Scott.
   2. (Printing) A piece of paper pasted upon the tympan sheet
      to improve the impression by making it stronger at a
      particular place.