Content Negotiation is employed via the 'ACCEPT' header.

HEADER Returned Content
Accept: text/html HTML
Accept: application/xhtml+xml HTML
Accept: text/turtle TTL
Accept: application/x-turtle TTL

Note: when HTML content is not available, the TTL content is returned.

Direct links of all ontologies

Right-click "Save link as..." to download
Ontologies are grouped by category, ordered by level of maturity and date of release
REC = recommendation, CR = candidate recommendation, WD = working draft, OLD = deprecated terms