Given its relevance, there is an extensive body of research for mod-eling variability in diverse domains. Regretfully, the community still faces issues and challenges to port or share variability models among tools and methodological approaches. There are researchers, for instance, implementing the same algorithms and analyses again because they use a specific modeling language and cannot use some existing tool. This paper introduces the High-Level Variability Language (HLVL), an expressive and extensible textual language that can be used as a modeling and an intermediate language for variability. HLVL was designed following an ontological approach, i.e., by defining their elements considering the meaning of the concepts existing on different variability languages. Our proposal not only provides a unified language based on a comprehensive analysis of the existing ones but also sets foundations to build tools that support different notations and their combination. CCS CONCEPTS • Software and its engineering → Domain specific languages; Software product lines.