Sui generis
Sui generis (; ) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."
Causa sui
Causa sui (, meaning "cause of itself" in Latin) denotes something which is generated within itself. This concept was central to the works of Baruch Spinoza, Sigmund Freud, Jean-Paul Sartre, and Ernest Becker, where it relates to the purpose that objects can assign to themselves. In Freud and Becker's case, the concept was often used as an immortality vessel, where something could create meaning or continue to create meaning beyond its own life.