It denotes a distinctive system of beliefs, myth, doctrine or theory that guides a social movement, institution, class or group. For example, baptise becomes baptism, a distinctive system of cleansing in water to testify to the forgiveness of sins. It is taken from the Greek fix -ismos, Latin -ismus, and Old French -isme.
An ism could refer to the suffix –ism; Interstellar medium; the initialism ISM; or even the band Ism, which is a New York based punk band. It could also refer to the International Solidarity Movement, which is a Palestinian-led movement that is devoted to resistance of the occupation of Palestinian territory by the Israeli military. It is committed to non-violent, direct-action principles and methods.
The term ism is often informal used to refer to a distinctive doctrine, theory or system. It could be a belief (or even a system of beliefs) that some group or school accepts as authoritative. In this sense of the term, synonyms for an ism would include the terms doctrine, philosophy, philosophical system and school of thought.
It could also be used to denote an oppressive and particularly discriminatory attitude or belief.
