Definitions

From OBO Foundry

Text vs computable definitions

Both clear english-language definitions and computable definitions should be supplied where appropriate. For "trivial" definitions of combinatorial terms the textual definitions may be generated automatically according to some standard form determined by the ontology editor

Genus differentia definitions

All definitions should be in genus-differentia form where possible.

E.g. "An X is a G that D"

Where D serves to differentiate instances of X from other instances of G.

Examples: TODO

In obo-format this can use intersection_of tags (see so-xp for examples). obo-format1.3 has a convenient syntax (based on Manchester OWL syntax) for representing thse definitional expressions: e.g. GO:0005634^OBO_REL:part_of(CL:0000127) for "a nucleus that is part of an astrocyte"