—Although there are contributions on component-oriented languages, components are mostly implemented using object-oriented (OO) languages. In this perspective, a component corresponds to a set of classes that work together to provide one or more services. Services are grouped together in interfaces that are each implemented by a class. Thus, dependencies between components are defined using the semantic of the enclosed classes, which is mostly structural. This makes it difficult to understand an architecture described with such links. Indeed, at an architectural level dependencies between components must represent functional aspects. This problem is worse, when the components are obtained by re-engineering of legacy OO systems. Indeed, in this case the obtained components are mainly based on the consistency of the grouping logic. So, in this paper we propose an approach to identify the interfaces of a component according to its interactions with the other components. To this end, we use formal concept analysis. The evaluation of the proposed approach via an empirical study showed that the identified interfaces overall correspond to the different functional aspects of the components.