a place out of sight: the cover someone watches or strikes from unseen, or where a person or a treasure is kept beyond finding
This is a place word built on the ordinary verb for hiding (סָתַר). It names the concealment and nothing more: who is hidden, and why, comes from the sentence around it. That is how one short word can cover a killer's vantage point, a buried royal treasure, and a prophet's private tears.
Most often the hidden one is dangerous. The poets set the word beside lions and bears, beside lying in wait, and beside an arrow loosed at someone who never sees the archer. What those verses press is not the place but the unfairness of it: the victim is in plain view and the attacker is not.
The rest of the word's use turns concealment into safety, or into the illusion of safety. Edom trusted places no raider would find, and Jeremiah says God stripped them open. A man may imagine some corner of the world puts him beyond God's sight, and Jeremiah 23:24 answers that God fills heaven and earth. Where the plural stands alone with no owner named, the sense thins to simply out of view, so that weeping "in secret" means weeping where nobody will see.
A nearby word from the same root (סֵתֶר) covers secrecy in general and also a protective covering. This word stays concrete and stays neutral about who benefits: it is the spot itself, and the verse decides whether being unseen there is a threat or a relief.