Okay kiddo, "idola fori" is a phrase in Latin that means "idols of the marketplace." It's related to the idea that language can be tricky and sometimes we don't realize when the words we use don't actually match reality.
Let's say you and your friends were talking about how big an elephant is. One of your friends says it's "huge", but another friend says it's "ginormous." Technically, both words mean "very big," but they don't actually give us any specific information about how big an elephant really is.
In a similar way, people might use words or phrases in their everyday talk that sound good, but don't actually represent accurate information about the world. These are the "idols of the marketplace."
This can be a problem when people make important decisions based on these flawed ideas. For example, if someone says "everyone knows that vaccines cause autism," even though that's not true, people might avoid vaccinations for their children and put them at risk of serious illness.
So, "idola fori" is a reminder to be careful with language and to make sure that the words we use actually match up with reality. It's one of those fancy Latin phrases that means "be honest with yourself and others about what you really mean."