With the goal of addressing open and dynamic scenarios like the Web, in this paper we introduce a semantic-oriented extension of the tuple space model. In our model, each tuple space is equipped with the ontological description of the coordination domain (e.g. expressed in W3C's OWL language). Tuples represent individuals of the domain along with their properties, and retrieval templates correspond to queries used to check whether an individual is the instance of an ontological concept (as typical in Description Logics, the logic of semantic reasoning). Differently from existing approaches in literature, we obtain a model that is fully expressive – compared to OWL – with a smooth extension of the standard syntactic setting of tuple spaces, namely, by an intuitive extension of the language for tuples and tuple templates. We discuss an incarnation of this model in the TuCSoN coordination model and infrastructure.