Sartre's BEING is a philosophical concept developed by French philosopher Jean-Paul Sartre. It refers to the idea that humans are responsible for their own actions and must take ownership of them. The term 'Etre' (4 letters) is the French word for 'BEING' and is used to refer to this concept. Sartre's BEING is an important part of his existentialist philosophy, which emphasizes the importance of individual freedom and responsibility.