There’s actually two definitions for corporatism. One relates to organizing society into collective groups (military, scientific, ect)
The other definition refers to dominance of corporations in capitalism.
Corporations aren’t just told to do under communism, they are owned by the government and told what to do. This, however, is not true for all socialistic ideologies like socialist anarchism. Socialism in its simplest form is mostly about eliminating private ownership by businesspeople and companies so the means to production can be shared by everyone apart of a company.
When it comes to private ownership, communists believe in government ownership while anarchists believe in self-interest and how owning things on your own that are essential (food, personal entertainment, housing, etc) is ok to be managed by the individual.