Definition(s):

Descriptive stereotypes are perceivers’ beliefs about the characteristics of a social group and indicate the attributes, roles, and behaviors that describe that group (Gill, 2004).
Prescriptive stereotypes depict the specific behavioral norms that individuals must uphold to avoid derogation or punishment by others (Gill, 2004).

Gill, M. J. (2004). When information does not deter stereotyping: Prescriptive stereotyping can foster bias under conditions that deter descriptive stereotyping. Journal of Experimental Social Psychology, 40, 619-632.