principle laid down as inconvertibly true in an ideology or belief system
A dogma is something that should not be disputed or doubted. Most often, this means the basic beliefs and doctrines of a religion. What a majority of followers of an ideology or any kind of organization believe in can also be a dogma.
In the context of religion, the term has a neutral meaning. Outside of religion for most people the term means something negative, because it accepts only a particular point of view. If someone disputes a religious dogma, they can be accused of heresy.
In Christianity, the Resurrection of Jesus is a basic dogma.