In the last years a rapid emergence of lexical resources evolved in the Semantic Web. Whereas most of the linguistic information is already machine-readable, we found that morphological information is either absent or only contained in semi-structured strings. While a plethora of linguistic resources for the lexical domain already exist and are highly reused, there is still a great gap for equivalent morphological datasets and ontologies. In order to enable the capturing of the semantics of expressions beneath the word-level, the Multilingual Morpheme Ontology (MMoOn) has been developed. It is designed for the creation of machine-processable and interoperable morpheme inventories of a given natural language. As such, any MMoOn dataset contains not only semantic information of whole words and word-forms but also information on the meaningful parts of which they consist, including inflectional and derivational affixes, stems and bases as well as a wide range of their underlying meanings.