What it means

1. noun a layer of decorative material (such as gold leaf or wood veneer) applied over a surface
2. noun 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
3. verb put something on top of something else
   “cover the meat with a lot of gravy”
4. verb kill by lying on
   “The sow overlay her piglets”