Definition: A discrete biological unit used when describing pathways. Comment: This is the root class for all biological concepts in the ontology, which include pathways, interactions and physical entities. As the most abstract class in the ontology, instances of the entity class should never be created. Instead, more specific classes should be used. Synonyms: thing, object, bioentity.
Source:http://www.biopax.org/release/biopax-level2.owl#entity