1. To arrange (open windows) on a computer desktop so that they overlap each other, with the title bars visible.
2. To rush down in big quantities, like a cascade; SYN. cascade down.

1. To coincide partially.
2. To concur partially or wholly
3. To extend over and cover a part of
4. To have something in common.

(Irregular preterit, past participle: overlaid).
To put something on top of something else; SYN. cover.