"Quantum theory is about tiny particles."
Translation:pay'anmey machqu' bop 'otlhQeD.
Sure, it's a theory. We all know the scientific definition of theory, right?
However, 'otlh nger means photon theory. 'otlh does not mean quantum, it means photon. The reason 'otlhQeD means quantum theory or quantum physics is that it literally means photon science, science of photons. The behavior of photons is governed by quantum physics. The phrase 'otlhQeD is given to us as correct, therefore we must accept it. The phrase 'otlh nger is not, so we can only interpret it literally.