Everything under this parent must be a mass noun. All subclasses are to be understood as being composed primarily of the named entity, rather than restricted to that entity. For example, "ENVO:water" is to be understood as "environmental material composed primarly of some CHEBI:water". This class is currently being aligned to the Basic Formal Ontology. Following this alignment, its definition and the definitions of its subclasses will be revised.

A portion of environmental material is a fiat object part which forms the medium or part of the medium of an environmental system.