The paper investigates a linguistic theory of stereotypes, cf. [Putnam 1975, Anscombre 2001, Bartminski 2012] in comparison with other theories of structured knowledge representations, such as prototypes [Rosch 1973, 1975, 1978], frames [Minsky 1975], idealized cognitive models [Lakoff 1987]. It is attested in literature that all these theories have a lot in common, and sometimes the notions of different theories are used as synonyms: Lyons (1995) regards stereotype and prototype as interchangeable terms, and Lakoff (1987) admits that his ICMs are similar to Putnam´s stereotypes, although more elaborated. While there are indeed some distinctions between stereotypes and other notions, their similarities seem more important: specifically, they allow the speaker to choose the simplest linguistic form if the entity corresponds to the norm, and help the hearer to recognize it easily and quickly.