State ownership
Public ownership of the means of production is a subset of social ownership, which is the defining characteristic of a socialist economy. However, state ownership and nationalization by themselves are not socialist, as they can exist under a wide variety of different political and economic systems for a variety of different reasons. State ownership by itself does not imply social ownership where income rights belong to society as a whole. As such, state ownership is only one possible expression of public ownership, which itself is one variation of the broader concept of social ownership.