Gluons are often depicted as fundamental particles in the Standard Model. But in looking at their mechanism, it seems they are not really fundamental particles in the sense that they are fundamental, indivisible, building blocks. They are mesons- a composite quark-antiquark pair, where their spin adds up to zero and therefore they act as guage bosons. And speaking of that, it seems even the weak force, the W bosons, can also be depicted equivalently as mesons, can't they? Am I misunderstanding this somehow?