Ontologies

Ashburner, M. et al. Gene ontology: tool for the unification of biology. The Gene Ontology Consortium. Nature Genet 25, 25–29 (2000).

Whetzel, P. L. et al. The MGED Ontology: a resource for semantics-based description of microarray experiments. Bioinformatics 22, 866–873 (2006).

Sequence Ontology (SO; http://song.sourceforge.net),

ontologies are used to describe the semantics (that is, the types of data that exist and the relationships between them)