Segregation: Segregation refers to the enforced separation of different racial, ethnic, religious, or social groups within society.
Border/Boundary: Borders/boundaries are lines that mark territorial limits between countries, states/provinces within a country or even smaller divisions like cities. They can create spatial divisions between different areas.
Gentrification: Gentrification is when wealthier residents move into an economically disadvantaged area and often leads to changes in demographics and increased spatial division between socioeconomic classes.