# Business Term (BT)

A standardized data element in EN 16931 (e.g., invoice number, VAT ID).

## Definition

A standardized data element in EN 16931 (e.g., invoice number, VAT ID).

## Explanation

BTs are referenced as BT-1, BT-2, etc.

XRechnung adds CIUS constraints on some BTs.

## Related resources

- [XRechnung field guide](/resources/xrechnung)

## Related terms

- [Business Group (BG)](/resources/glossary/business-group-bg): A logical group of business terms in EN 16931 (e.g., seller info, totals).
- [EN 16931](/resources/glossary/en-16931): European standard defining the semantic data model for e-invoices.
- [XRechnung](/resources/glossary/xrechnung): German e-invoicing specification for the public sector based on EN 16931.