The notion of ontology modularization refers to a methodological principle in ontology engineering. The idea is that an ontology is built in a modular manner, i.e. developed as a set of small modules and later composed to form, and be used as, one modular ontology.
One of the major research meetings on ontology modularization is the International Workshop on Modular Ontologies series.
References
Ontology modularization Wikipedia(Text) CC BY-SA