Taxonomies and ontologies are similar in many ways. Both of them are helpful in information organization, categorization and classification. So ontology is easy confused with taxonomy, and vice versa.
In my mind,
(a) A taxonomy is hierearachical DAG or tree...
(b) An ontology is a metagraph...
- Quora discussion on taxonomy and ontology.
- A cureated resource for taxonomy research 📑 awesome-taxonomy.