The definition of a noun used to be so simple You may even remember your elementary school teachers telling you a noun was a person, place or thing. Then it got a little more complicated when they added “idea” to the list. Then it got even more confusing when you asked about “coffee” in “coffee table.” Is it a noun or an adjective? What about when you add an apostrophe and “s” to it to show possession? Is it still a noun, or does it become an adjective? And round and round you go. It’s exhausting, but there are answers.