We discuss the semantics of prenominal "zero", as in 'I have zero new emails in my inbox'. We show that 'zero' is not a quantifier like "no" and that giving "zero" a regular numeral semantics is possible and desirable. We formulate such an analysis and its consequences. We show that the existence of a zero numeral has profound consequences for linguistic semantics. We conclude that the fact that languages allow ascription of zero quantity to an entity provides evidence that linguistic semantics has access to what at first sight may seem like an ontological oddity: an entity with zero quantity. In other words, we will show that studying "zero" can inform us about the underlying semantic ontology of natural language.