The term "social defence" is used to describe non-military action by a society or social group, particularly in a context of a sustained campaign against outside attack or dictatorial rule – or preparations for such a campaign in the event of external attack or usurpation. There are various near-synonyms, including "non-violent defence", "civilian defence", "civilian-based defence", and "defence by civil resistance". Whatever term is used, this approach involves preparations for and use of a range of actions – which can be variously called nonviolent resistance and civil resistance – for national defence against invasion, coup d'état and other threats.