Sacred cow (idiom)

Okay little one, you know how sometimes people have things that they really believe in and think are really important and special? Well, imagine if one of those things was a cow. But this cow wasn't just any ordinary cow, it was very special and important to these people. They think that if anything bad happened to this cow, it would be very very bad luck and everyone would be really upset. So they call this cow a "sacred cow" because it is holy and cannot be touched or harmed in any way.

Now, when people use the phrase "sacred cow" as an idiom, they're not talking about a real cow that's holy. They're talking about ideas or beliefs that people have that are so important to them that other people are afraid to question or challenge them. It's like if your mom always makes you eat your vegetables even if you don't like them, and if you said "I don't want to eat them!" she might get upset and say "But you have to, it's good for you!" That rule about always eating vegetables might be her "sacred cow" because she thinks it's really important, even if you don't like it. Does that make sense, little one?