You might have come across the term ‘ontology’ in the biomedical literature or in a database. You might have knowingly or unknowingly used it to query data. An ontology consists of well-defined terms that describe entities (for example, the entity might be a gene) and the relationships between them. The goal of building an ontology is to reflect the current knowledge in a particular domain using a controlled vocabulary, to provide a guide for organizing new data, and to allow users to conduct queries. The Worm Phenotype Ontology (WPO) is a hierarchically structured, controlled vocabulary of terms that can be used to standardize phenotype descriptions in C. elegans. Although the WPO was created in order to help manage and disseminate C. elegans phenotypic data, it is not exclusively limited to C. elegans biology, but rather devised to also incorporate phenotypes observed in related nematode species. The WPO will help facilitate data retrieval, and cross-species comparisons within the nematode community and in the larger scientific community, will permit data integration, and interoperability across different biological databases. We are actively developing the WPO to continue to fulfill the evolving needs of the scientific community and hope to engage researchers in this crucial endeavor. To know more, please visit this recent publication that describes the WPO: http://www.biomedcentral.com/1471-2105/12/32