Is there an ontology for ontologies?


Is there somewhere an ontology for ontologies? What would it need?

intended domain
collateral domains
specialization of (some ontology)
generalization of (some ontology)
synonyms (in other ontologies)
antonyms (in other ontologies)
type of (ontological) structures
structure (of this ontology)
main features
based on (foundation ontologies)
links to (other ontologies)
representational units
composite representations
sounds like

btw @MitziLaszlo, can we add a Linked Data or Linked Data for Solid category?


Did you look at owl that describe ontology, version of ontology, doc of ontology…


That seems to be used just to point to different ontologies instead of describing more general differences between them, unless I’m missing something?

An ontology of ontologies would be useful to describe ontologies so they could be found on a pod according to what they do and how they’re related, also maybe some measures of their adoption.


Something like Active ontology tab in Protege ?


Is the ‘active ontology’ an ontology or just the current on that is ‘active’ in the protege tool?

edit: thanks, that led me to


Nice find!


they say

“We are also currenlty discussing MOD 2.0 that would be designed as a profile of DCAT.”

then from :

“A DCAT profile is a specification for a data catalog that adds additional constraints to DCAT. A data catalog that conforms to the profile also conforms to DCAT.”

and Dcat has an alignment with

So I don’t know where its all going :slight_smile:


I don’t know of an ontology of ontologies per se, but as @Smag0 pointed out, a lot of the features you describe may be achieved using a combination of well-known ontologies:

  • specialization/generalization/extension of vocabularies can be captured with Vocabulary Of A Friend (VOAF):, see specializes or extends
  • Synonyms and antonyms can (somewhat) be captured with OWL, with olw:sameAs and owl:disjointWith.
  • Links to can be materialized with rdfs:seeAlso
  • The Intended domain can be referenced with foaf:primaryTopic, and collateral domains with foaf:topic
  • You could be interested in discussion about ontological structures seen as desig patterns:

I’m interested in the follow-up on DCAT :wink:


That question invite me to propose all a new app that allow us to share that kind of knowledge in a decentralized way :
Tension created that everyone can edit :blush:


Just as its empire is falling apart, the U.S. government seems to be beginning to get some linked data together. At

they have a link to a dcat schema called the Project Open Data Metadata Schema at

They abbreviate Project Open Data with POD :slight_smile:

Also, from,

"A general issue is determined by the fact that and DCAT-AP address different use cases. More precisely, the main purpose of is to enhance discovery and indexing of online resources via search engines. As such, it is addressing more general objectives compared with DCAT-AP, that is instead meant to model in detail information on datasets and data catalogues.

One of the main consequences is that some information that is relevant in DCAT-AP it is not modelled in with specific terms. This results in a relevant amount of (a) “missing” and (b) “many-to-one” mappings - i.e., different metadata elements of DCAT-AP are mapped to the same element in"


@tag42git yes of course


Unfortunately with DCAT they appear to be developing yet another ‘standard’. It isn’t RDF and I’m not sure it is even JSON-LD.

From my reading it seems to be either a subset of JSON-LD or is a non RDF compliant form of JSON-LD which will make it difficult to work with using tools and libraries that are built for RDF.

It isn’t clear, but it may be that they’ve designed it so that they can consume RDF compatible JSON-LD, but not the other way around. Kind of parasitic.

Perhaps someone who understands the technicalities better than me can correct or confirm.


oh wow thank you, are you sure?


"DCAT is an RDF vocabulary designed to facilitate interoperability between data catalogs published on the Web. "

The U.S. government parasitical? :scream:


Hopefully I am wrong and your link does make it clear that DCAT is an RDF ontology.

I think my question is whether they are using it to describe RDF resources or not because the description of its use doesn’t mention RDF, only JSON and JSON-LD, and describes how much of the JSON-LD is optional which I’m taking as meaning it is not RDF compliant.

However, for your purposes you can still use DCAT in RDF resources.

So maybe it is more that they are using an RDF ontology to define their non RDF compliant schema?


I just asked at


Feedback at so far seems to indicate dcat is the goto ontology


Thanks to @sideshowtom in the chat : Vocabulary of Linked Datasets - how cool is that!