Intersectionality was coined in 1989 by Kimberlé Crenshaw to describe how race, class, gender, and other individual characteristics "intersect" with one another and overlap. "What intersectionality means in practical terms is that people who are situated differently are not only likely to have considerably different needs, concerns, and experiences but that the interests of more powerful members of a group may predominate and define their political agenda. However, it should be noted that intersectional approaches reject fixed social categories and unidirectional notions of power and assume that people’s social positions are both fluid and multiple."
Identity: "Identity refers to a person’s social group or category which is assumed to imply connection or sameness, such as gender or sexuality or nationality, or to a larger sense of self (“who I am”) to which the specific identity categories are assumed to contribute. Identity therefore raises issues of the connection, or lack of it, between the social identities imposed by others, such as a racial identity, and the personal identity claimed by a person as part of her or his self-identification and the connections between different categories of identity."
Intersectionality as Critical Social Theory by 
Theorizing Intersectionality and Sexuality by 
Affirmative Advocacy: Race, Class, and Gender in Interest Group Politics by 
Poverty, Racism, and Sexism : The Reality of Oppression in America by