'Understood' in the Bible

Once again, for the third time, the Lord called Samuel. He got up, went to Eli, and said, “Here I am; you called me.”Then Eli understood that the Lord was calling the boy.

Then Eli understood that the LORD was calling the boy, so Eli told Samuel, "Go lie down, and then if he calls you, answer, "Speak, LORD, because your servant is listening.'" Then Samuel went and lay down.

And when the Philistines heard the noise of the shout, they said, What meaneth the noise of this great shout in the camp of the Hebrews? And they understood that the ark of the LORD was come into the camp.

The servant was not aware of anything. Only Jonathan and David understood what had happened.

David therefore sent out spies, and understood that Saul was come in very deed.