What word or phrase does your mother always say?
1798, "method of printing from a plate," from French stéréotype (adj.) "printing by means of a solid plate of type," from Greek stereos "solid" (see sterile) + French type "type." Noun meaning "a stereotype plate" is from 1817. Meaning "image perpetuated without change" is first recorded 1850, from the verb in this sense, which is from 1819. Meaning "preconceived and oversimplified notion of characteristics typical of a person or group" is recorded from 1922. Stereotypical is attested from 1949.
A too-simple and therefore distorted image of a group, such as “Football players are stupid” or “The English are cold and unfriendly people.”
A generalization, usually exaggerated or oversimplified and often offensive, that is used to describe or distinguish a group.