'Threshing floor' in the Bible

So then, [is] not Boaz our kinsman whose maidservants you were with? Look, he [is] winnowing the barley at the threshing floor tonight.

Wash, anoint yourself, put your clothing on, and go down to the threshing floor. Do not make yourself known to the man until he finishes eating and drinking.

And she went down to the threshing floor and did all that her mother-in-law had instructed her.

So she lay at his feet until morning and got up before {anyone could recognize each other}. And he said, "It must not be known that {you} came [to] the threshing floor."