For Andrew Vincent, "[t]he word ‘socialism’ finds its root in the Latin sociare, which means to combine or to share. The related, more technical term in Roman and then medieval law was societas. This latter word could mean companionship and fellowship as well as the more legalistic idea of a consensual contract between freemen".
The term "socialism" was created by Henri de Saint-Simon, one of the founders of what would later be labelled "utopian socialism". Simon coined "socialism" as a contrast to the liberal doctrine of "individualism", which stressed that people act or should act as if they are in isolation from one another. The original "utopian" socialists condemned liberal individualism for failing to address social concerns during the industrial revolution, including poverty, social oppression and gross inequalities in wealth, thus viewing liberal individualism as degenerating society into supporting selfish egoism that harmed community life through promoting a society based on competition. They presented socialism as an alternative to liberal individualism based on the shared ownership of resources, although their proposals for socialism differed significantly. Saint-Simon proposed economic planning, scientific administration and the application of modern scientific advancements to the organization of society. By contrast, Robert Owen proposed the organization of production and ownership in cooperatives.
The term "socialism" is also attributed to Pierre Leroux and to Marie Roch Louis Reybaud in France; and in Britain to Robert Owen in 1827, father of the cooperative movement.
The modern definition and usage of "socialism" settled by the 1860s, becoming the predominant term among the group of words "co-operative", "mutualist" and "associationist", which had previously been used as synonyms. The term "communism" also fell out of use during this period, despite earlier distinctions between socialism and communism from the 1840s. An early distinction between socialism and communism was that the former aimed to only socialise production while the latter aimed to socialise both production and consumption (in the form of free access to final goods). However, Marxists employed the term "socialism" in place of "communism" by 1888, which had come to be considered an old-fashion synonym for socialism. It was not until 1917 after the Bolshevik Revolution that "socialism" came to refer to a distinct stage between capitalism and communism, introduced by Vladimir Lenin as a means to defend the Bolshevik seizure of power against traditional Marxist criticisms that Russia's productive forces were not sufficiently developed for socialist revolution.
A distinction between "communist" and "socialist" as descriptors of political ideologies arose in 1918 after the Russian Social-Democratic Labour Party renamed itself to the All-Russian Communist Party, where communist came to specifically mean socialists who supported the politics and theories of Leninism, Bolshevism and later Marxism–Leninism, although communist parties continued to describe themselves as socialists dedicated to socialism.
The words "socialism" and "communism" eventually accorded with the adherents' and opponents' cultural attitude towards religion. In Christian Europe, communism was believed to be the atheist way of life. In Protestant England, the word "communism" was too culturally and aurally close to the Roman Catholic communion rite, hence English atheists denoted themselves socialists. Friedrich Engels argued that in 1848, at the time when The Communist Manifesto was published, that "socialism was respectable on the continent, while communism was not". The Owenites in England and the Fourierists in France were considered "respectable" socialists, while working-class movements that "proclaimed the necessity of total social change" denoted themselves communists. This latter branch of socialism produced the communist work of Étienne Cabet in France and Wilhelm Weitling in Germany. The British moral philosopher John Stuart Mill also came to advocate a form of economic socialism within a liberal context. In later editions of his Principles of Political Economy (1848), Mill would argue that "as far as economic theory was concerned, there is nothing in principle in economic theory that precludes an economic order based on socialist policies". While democrats looked to the Revolutions of 1848 as a democratic revolution, which in the long run ensured liberty, equality and fraternity, Marxists denounced 1848 as a betrayal of working-class ideals by a bourgeoisie indifferent to the legitimate demands of the proletariat.