In the book "Middlesex" by Jeffrey Eugenides, the author introduces the concept of a "Hair Belt," akin to well-known regions like the Sun Belt and Bible Belt. This metaphor suggests that just as these areas are defined by certain cultural or regional characteristics, the Hair Belt represents a unique facet of identity, relating to how hair serves as a symbol of classification and belonging in society.

The idea of the Hair Belt also implies a deeper exploration of personal and cultural identity. Hair can reflect various aspects of ethnicity, gender, and social status, tying into broader themes of transformation and self-discovery that are central to the narrative of "Middlesex." The notion invites readers to consider how external appearances, such as hairstyle, can carry significant meaning and contribute to one's sense of place in the world.