Since the comparison is with itself, the main difference lies in context. The term 'First Lady' typically refers to the spouse of a head of state, often involved in ceremonial duties and public service. It is not a formal job with specific credentials but a role often filled by a prominent figure in society. The role varies widely depending on the country and individual. Unlike formal positions, the First Lady role is unofficial and non-paid, focusing on advocacy, charity work, and representing the nation in social events.