Final answer:
A minority group is defined as a category of people who experience differential and unequal treatment due to their physical or cultural characteristics.
Step-by-step explanation:
A minority group is defined as a category of people who, because of their physical or cultural characteristics, are singled out from the others in the society in which they live for differential and unequal treatment, and who therefore regard themselves as objects of collective discrimination. This definition was provided by sociologist Louis Wirth in 1945. Additionally, minority groups are distinguished by characteristics such as unequal treatment and less power over their lives, distinguishing physical or cultural traits, involuntary membership, awareness of subordination, and high rates of in-group marriage.