A VAT number (or value added tax identification number) is a number used by countries within EU (and outside) for purposes related to VAT or Value Added Tax.

On the Record Union website, a VAT number is needed in order to receive royalty payments as a company based in the EU. Without this number we would not be able to comply with the EU regulations governing sending payments to other companies.

VAT numbers may have a different name in the country you are located in.

Please see this Wikipedia article which provides an additional country specific info concerning VAT numbers.