The concept of capability is a cornerstone element in service description. Nevertheless, despite its fundamental role little effort has been seen to model service capabilities. Current approaches either fail to consider capabilities as feature-based entities and confuse them with annotated invocation interfaces or fail in modelling capabilities at several abstraction levels and establishing links between them. In particular, they are not able to model and deal with concrete capabilities (i.e., capabilities that reflect real customers' needs). In this paper, we propose a conceptual model as an RDF-schema for describing service capabilities. Our model defines capabilities as an action verb and a set of attributes and their values. It is also able to define capabilities at different levels of abstractions/concreteness and establish links between them. Most importantly, our model enables describing concrete capabilities which directly correspond to consumer needs. Our meta model is based on RDF and makes use of Linked Data to define capability attributes as well as their values.