ELI5: Explain Like I'm 5

Olly olly oxen free

"Olly olly oxen free" is a phrase you might say when playing a game of hide and seek or tag with your friends. It means that everyone who is hiding can come out into the open or "home base" without getting tagged or caught. So it's like a way of saying "come out, come out, wherever you are" and letting everyone know that the game is over. It's a fun way to end the game and make sure no one is left hiding or feeling left out.
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