The notion of context seems to be a growing subject in the engineering sciences. Several studies have pointed out the necessity to address the contextual limitations in collaborative design projects. It has been identified as one of the major factors that contribute to inadequate knowledge reuse in design projects. Nevertheless, the definition of the context depends on the subject and the field of application. In this paper, we point out different definitions of the context in artificial intelligence, engineering and cognitive sciences. In this research study we present a proposition for context modelling representing only one part of collaborative decision-making support. The research study presented in this paper is a result of collaboration with one of the French car manufacturers. Within the conceptual model of collaborative decision-making, we propose to integrate the information concerning three different contexts: decision, project and enterprise context. The aim of this model is to help and support the project team in project management.