There is no fixed definition. Marxists today use different words to Lenin and Trotsky, and they in turn used different words to Marx.
Nowadays we just talk about socialism. The word communism is rarely used.
Lenin and Trotsky talked of first a transitional phase to socialism, and the on to communism. They never got as far as socialism.
Marx and Engels did not call themselves socialists, they talked about a transitional phase to a lower stage of communism which would then evolve to a higher stage.
Its just how words get used differently over time. At one time the Marxists were in Social Democratic parties, nowadays social democracy means in the middle, mixing capitalism with state involvement on behalf of the workers.
Marx did not consider himself a utopian at all. He concentrated on the here and now, not speculating about models of socialist societies.
Sandori
So I'm an anarchist?
dont be an anarchist, they wasted their chance in Spain and they spent half their time in Russia on the enemy side. The aim of anarchists is communism, but they think they can go straight to it. However you need a workers state first to defend against attacks from capitalism, and organise industry. The Bolsheviks had a democratic workers state which the anarchists were free to take part in but declined. Makhno, one anarchist leader, set up a mini state anyway, but a sort of gangster state, robbing trains and so on. He was only interested in the peasants, not the workers, but the peasants were not very interested in him. He formed an army and sometimes sided with the Bolsheviks, sometimes against. The anarchists tell a lot of lies about him, due to being misinformed, but I have access to some very good information. Similarly at Kronstadt the anarchists mostly sided with the mutineers who were endangering the whole revolution.
ingliz
Communism is the economically abundant, classless, stateless society that revolutionary socialists aspire to, where goods are distributed to individuals according to their need. It must be understood that this means that there is only an equality in satisfying needs. All individual needs and wants are different, and will be met in a communist society, so no boiler-suited conformity here.
Socialism, like capitalism, is conditioned by economic scarcity. Scarcity is the fundamental economic problem of having seemingly unlimited human needs and wants, in a world of limited resources, but this need not mean that socialists are condemned to a basic, dull, grey, anonymous, uniformity anymore than capitalists are.
This is a good definition. What I would add is that to get socialism you have to be in a position where elimination of scarcity is feasible and reasonably imminent, with good progress being made.
Marx famously said
"this development of productive forces (which itself implies the actual empirical existence of men in their world-historical, instead of local, being) is an absolutely necessary practical premise because without it want is merely made general, and with destitution the struggle for necessities and all the old filthy business would necessarily be reproduced" where filthy business means capitalism.
Lenin said in 1922
"we have not finished building even the foundations of socialist economy" in 1922, saying that socialism would be doomed if Russia was isolated
"we have always urged and reiterated the elementary truth of Marxism - that the joint efforts of the workers of several advanced countries are needed for the victory of socialism" Marx:
Communism is for us not a state of affairs which is to be established, an ideal to which reality [will] have to adjust itself. We call communism the real movement which abolishes the present state of things. The conditions of this movement result from the premises now in existence. German Ideology
"in reality it was the Communists above all others who prevented revolution in Spain" George Orwell
Economic Left/Right: -10.0 Social Libertarian/Authoritarian: -8.31