The difference between race and ethnicity in Black identity politics is not semantic — it is structural. In American law and census classification, race operates as a broad social category shaped by power hierarchies. Ethnicity, by contrast, refers to shared lineage, culture, and historical continuity. As debates grow around lineage-based identity, reparations eligibility, and census data disaggregation, this distinction becomes central. Is “Black” a race, an ethnicity, or both? And how does that classification affect constitutional scrutiny, policy design, and civic cohesion? This analysis explains how race and ethnicity function differently in the United States — and why precision is necessary before political conclusions are drawn.