The issue is one of legal status. In most countries you can be a commercial company or essentially a branch of the government (leaving aside coops and charities).

So in general you have companies (legal status) but they are fully owned by the state, hence "state-owned company". "Privatized" means the government decided to sell most or all the shares to the public.

Counter example is the USPS in the US, which is an agency of the Federal government.