O'Casey is typically used to refer to the Irish playwright, Sean O'Casey. However, there are several synonyms that can also be used to denote this name. These include Sean Casey, Seán Ó Cathasaigh, and John Casey. These names are often used interchangeably by biographers, researchers, and scholars discussing the life and works of this legendary playwright. Sean O'Casey is particularly well-known for his portrayal of Irish life during the early 20th century in plays like "Juno and the Paycock" and "The Plough and the Stars," which explore themes like poverty, conflict, and social divisions. His literary legacy continues to inspire a new generation of writers and artists.