I have the impression from my (limited, autodidactic) reading of Marx that he was antagonistic towards various forms of Socialism, criticizing Socialists for being (among other things) piecemeal reformers who remained bound by the economic relations of existing societies, and who de-emphasize class struggle and revolutionary expression by the proletariat, (in the Communist Manifesto section III. SOCIALIST AND COMMUNIST LITERATURE)
But on the wikipedia page for "Types of Socialism" I read,
In Marxist theory, socialism refers to a specific stage of social and economic development that will displace capitalism, characterized by coordinated production, public or cooperative ownership of capital, diminishing class conflict and inequalities that spawn from such and the end of wage-labor with a method of compensation based on the principle of "From each according to his ability, to each according to his contribution".
I see the quote, "From each according to his ability, to each according to his contribution" is not from Marx himself but an interpretation of the "Critique of the Gotha Program" in which Marx critically regards this stage as an inevitable first phase of communist society as it emerges from capitalist society, but Marx does not (as far as I can see) use the word "socialism" to describe this form of nascent communism. Marx goes on to describe a "higher phase of communist society", a utopia characterized by "From each according to his ability, to each according to his needs!"
Would Marx himself have described this nascent stage of communism as "socialism" of do later Marxist theorists, notably those charged with implementing a Marxist society, use the word "socialism" in a different sense to Marx, to bridge (fudge?) over the gap between Marx's utopian vision and the practical considerations of incentivizing workers?