The social economy was born in the 19th century with groupings of persons united by a common will (affectio societatis) rather than a ‘nexus of commercial contracts’. When the term ‘enterprise’ first appeared, it originally referred to the very general sense of ‘undertaking’ before the social economy adopted it in 1977 with the expression ‘social economy enterprise’ to emphasise the unity of the social economy despite its variety of legal forms and differentiate it from the conventional company model. This article retraces this history. It shows the growing acceptance of the idea of the society until 1860 as the organisational form of most of the solidarity and democratic initiatives (I). In the early 20th century, the idea of the enterprise appeared via cooperatives, which were always regarded as secondary to voluntary organisations (II) before gradually separating and extending to the whole social economy (III).