Hazing is an often ritualistic test, which may constitute harassment, abuse or humiliation with requirements to perform meaningless tasks; sometimes as a way of initiation into a social group. The term can refer to either physical (sometimes violent) or mental (possibly degrading) practices. The word is most frequently encountered in the United States and Canada; in the British Commonwealth ragging or fagging is usually used instead. In continental European languages terms with a 'christening' theme or etymology are often preferred (e.g. baptême in French) or variations on a theme of naivety and the rite of passage such as a derivation from a term for freshman (e.g. bizutage in French, ontgroening 'de-green[horn]ing' in Dutch).
Often most or all of the endurance, or at least the more serious ordeal, is concentrated in an orgy-like session, which may be called hell night, or prolonged to a hell week and/or retreat or camp, sometimes again at the pledge's birthday (e.g. by birthday spanking), but some traditions keep terrorizing pledges (a common term for the initiation candidates; alternative terms include newbie, rookie, mainly in athletic teams, and freshman) over a long period, resembling fagging.
Hazing is often used as a method to promote group loyalty and comaraderie through shared suffering, either with fellow participants, past participants, or both.
A tentative explanation from evolutionary psychology is that grave hazing can activate the capture-bonding psychological trait also known as Stockholm syndrome.