'Certain' in the Bible

He came to a certain place, and stayed there all night, because the sun had set. He took one of the stones of the place, and put it under his head, and lay down in that place to sleep.

A certain man found him, and behold, he was wandering in the field. The man asked him, "What are you looking for?"

It happened at that time, that Judah went down from his brothers, and visited a certain Adullamite, whose name was Hirah.

Judah saw there a daughter of a certain Canaanite whose name was Shua. He took her, and went in to her.