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This glossary gives definitions for the main regulatory terms used on this website and in European Medicines Agency (EMA) documents.

Click on a letter below to see terms beginning with that letter.

Disclaimer: EMA has developed the definitions in this glossary to help this website's users understand regulatory terminology. Definitions may differ from those given in European Union legislation.


off-label use

Use of a medicine for an unapproved indication or in an unapproved age group, dosage, or route of administration.

Official Journal of the European Union

Daily European Union publication publishing legal instruments and other European Union documents.

For more information, see Official Journal of the European Union.

official medicines control laboratory

A European laboratory, independent from pharmaceutical companies, that supports regulatory authorities by controlling the quality of medicinal products for human or veterinary use.

For more information, see general European official medicines control laboratory network.

oral explanation

A presentation and discussion in person between representatives of an applicant and a European Medicines Agency committee.

orphan designation

A status assigned to a medicine intended for use against a rare condition. The medicine must fulfil certain criteria for designation as an orphan medicine so that it can benefit from incentives such as protection from competition once on the market.

For more information, see orphan designation.

orphan medicine

A medicine for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition that is rare (affecting not more than five in 10,000 people in the European Union) or where the medicine is unlikely to generate sufficient profit to justify research and development costs.

For more information, see medicines for rare diseases.