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
a layer of decorative material (such as gold leaf or wood veneer) applied over a surface
Verb:
put something on top of something else;
"cover the meat with a lot of gravy"
kill by lying on;
"The sow overlay her piglets"
overlay的用法和样例：
例句
用作动词 (v.)
Psionic tattoos cannot overlay one another. 一幅灵纹不会覆盖另一幅。
Overlay it with pure gold and make a gold molding around it. 要包上纯金,四围镶上金牙边。
I'm not very sure how to import a document or how to overlay a picture onto a text. 我不太清楚怎样应用文档，以及如何把一张图片叠加在文本上去。
