Here is the definition of oxide I found in a dictionary: A compound of one oxygen atom combined with another element. And here is the definition of dioxide that I found in a dictionary: An oxide containing two atoms of oxygen in each molecule; binoxide. Now my question/confusion is, according to the above definitions I'm thinking to myself that if an oxide is just ONE compound/molecule, that's composed of an atom of oxygen and another element, then howcome for the definition of dioxide it says, "An oxide containing two atoms of oxygen in EACH molecule"!? So what's the deal? Does an oxide consist of only one molecule or more?!