What is the term for hereditary systems of rank that tend to be fixed and immobile?

The term for hereditary systems of rank that tend to be fixed and immobile is known as castes. In a caste system, individuals are born into their social position, and this position typically remains unchanged throughout their lives. This is characterized by strict social stratification, where movement between different levels is largely impossible due to social norms, cultural traditions, and sometimes legal restrictions.

Caste systems often dictate not only the profession that one might pursue but also influences personal relationships, including marriage and association. The nature of this immobility is a defining characteristic that differentiates castes from classes, which can involve more fluidity and opportunities for social mobility based on factors such as income, education, and individual achievements. Understanding this concept is essential in the study of social stratification and the various forms in which it can manifest in society.