what does ism mean
â¢ ISM (noun). The noun ISM has 1 sense: 1. a belief (or system of beliefs) accepted as authoritative by some group or school. Familiarity information: ISM used as a noun is very rare.irondism (the doctrine of the Girondists). functionalism (any doctrine that stresses utility or purpose). formalism (the doctrine that formal structure rather than content is what should be represented). expansionism (the doctrine of expanding the territory or the economic influence of a country).