Dutchman has as good a differentiation as I have seen:
My daughter Zoe once got in trouble at school for defining the difference between communism and socialism. Not surprisingly, she repeated the short answer that I had taught her: “The difference between a communist and socialist is that a socialist is a communist who has not found his AK-47 and the will to use it, and a communist is a socialist with an AK-47 who IS ready to use it.”
I was called by the “social studies” teacher on that one and went into the school for a visit. What, I asked was wrong with that answer? As he sputtered, I asked a second question. “Have YOU ever been a socialist or a communist?” “Well, no,” he answered. “Let me tell you something then — I have been BOTH a socialist AND a communist and believe me I know what I’m talking about and you most definitely do not.” My daughter was not disciplined.”
He then goes on to remember the Communist’s slaughter of thousands at ‘The Liberation of Hue City”.