State ownership of all companies, yes, that's one implementation of socialism though not "literally the definition". But obviously this isn't how China is now and even state-owned companies in China generally operate in a market and can be in competition with private companies and other state-owned companies. In fact the Chinese eoconomy is probably more competitive that in the West now, it is fierce competition for profit with generally free enterprise.

There are state-owned companies in all Western countries, by the way.

I don't think that you are familiar with the history and economy of China.