Voted "other".
Communism is an economical system where the means of production are owned collectively. This ownership *in theory* does not have to represent a party or any authority of any kind. In fact, the absence of central authority is the point of communism.
The theoretical build of communism resemble enormously a form of enlightened anarchy, and it's not a "social system" just like bald is not a hairstyle - it's more about the lack of a "social system", which *should* have been outgrown by humanity by the time communism is reached.
To bury from scratch a common misconception, in communism there
is private property - as long as the property is not a mean of production. That means you can keep from your underpants to your family jewels - what you "can't" own individually is a farm or a factory (I put this in quotation marks because in theory, this is less about "prohibition" than about the "extinction of the concept of owning supra-individual goodies").
Socialism, on the other hand, is an embryo, a transition formula between capitalism and communism, where a powerful central authority (not necessarily dictatorial) is committed to the redistribution of means of production. The failure of the communism theory seems to be that socialism, the intermediary, tends to deform into tyrannical entities (aberrations such as Stalinism, Maoism and Castrism) to perpetuate itself, and create a bureaucratic elite instead of s capitalistic elite, falling to the same problems of the previous system, added with a whole bunch of problems of its own.
Thing is, the theory of communism adopted the idea of armed resolution (probably, influenced by the successes of the French Revolution and of the US independence, which have given the world the impression that you could really change things with a will to fight and a noble heart), but it was very poorly executed in real world specially because communism was envisioned originally as the path of development of a rich and modern society, where the wealthy of capitalism and the conscientiousness of people mixed together, creating the means and the mindset for the proletarians to take over.
What happened in the real world was the contrary. Poor, backwards countries adopted it as means to destroy failing states and rebuilt them with a new grand vision, without abiding to its theoretical construct, no less. Quite frankly, its no surprise it was such a failure.
Regards
.