Final answer:
W.E.B. Du Bois used the term 'the Color Line' to describe the societal and physical separation between races, specifically between Black and White individuals. This concept also encompasses the invisible separation known as 'the Veil' that differentiates the cultural and social worlds of these groups.
Step-by-step explanation:
The term W.E.B. Du Bois used to represent skin color or race is 'the Color Line'. This concept was introduced by Du Bois to describe the division between different racial groups, particularly between Black and White citizens. The Color Line can be an invisible societal barrier, or at times, it manifests as a very real physical separation. Du Bois also discussed 'the Veil,' which symbolizes the separate worlds inhabited by Black and White people. The veil is an intangible separation that segregates these two groups culturally and socially.
Historical tensions and classifications have been based on superficial characteristics like skin tone, rather than biological or ancestral factors. For centuries, the perceived superiority or inferiority within racial groups has been a driving force of inequality and division. The most notable era of legally-enforced racial segregation may have ended with the Civil Rights Movement, but the impacts of this division have persisted in societal attitudes and institutional structures.