I suppose socialism, in the strictest definition of the word, means state ownership of industry, but throughout the decades it has been warped and realigned so many times that by now it means many different things to many different people.
The original European socialists were anarchist-leaning, same as the original European liberals. Nationalization and regulation are the manifestation more of policies like the German SDP, then the UK Labor, and similar state socialist parties. The fact that academics and observers feel the need to add the modifier "state" in front of socialist should suggest that it might have a very different meaning alone.