Pacifism is the opposition or resistance to war, militarism or violence. The word pacifism was coined by the French peace campaigner Émile Arnaud and adopted by other peace activists at the tenth Universal Peace Congress in Glasgow in 1901. A related term is ahimsa, which is a core philosophy in Indian religions such as Hinduism, Buddhism, and Jainism. While modern connotations are recent, having been explicated since the 19th century, ancient references abound.

Nonviolence is the personal practice of not causing harm to others under any condition. It may come from the belief that hurting people, animals and/or the environment is unnecessary to achieve an outcome and it may refer to a general philosophy of abstention from violence. It may be based on moral, religious or spiritual principles, or the reasons for it may be strategic or pragmatic. Failure to distinguish between the two types of nonviolent approaches can lead to distortion in the concept's meaning and effectiveness, which can subsequently result in confusion among the audience. Although both principled and pragmatic nonviolent approaches preach for nonviolence, they may have distinct motives, goals, philosophies, and techniques. However, rather than debating the best practice between the two approaches, both can indicate alternative paths for those who do not want to use violence.