1.VerbUsed other than figuratively or idiomatically: see lay, foundation.
2.VerbTo elicit information from a witness to show that the witness has knowledge of a matter before the witness testifies to the matter itself.
"In order to lay a foundation for the witness to describe the murder, the prosecutor first had to show that the witness was present when the murder occurred."
3.VerbTo make a start.
"You should lay a foundation, even if you can't finish the project."