Dogma means the doctrine of belief in a religion or a political system.
The literal meaning of dogma in ancient Greek was "something that seems true." These days, in English, dogma is more absolute. If you believe in a certain religion or philosophy, you believe in its dogma, or core assumptions. If you belong to a cult that believes that cupcake consumption is the only true path, then you follow the cupcake dogma. Dogma, once adopted, is accepted without question. Go eat cupcakes!