Glossary¶

E-invoicing runs on acronyms. This page defines them in plain language, grouped by what they are rather than alphabetically, so the relationships are visible. Each term links to where it is used in depth.

Standards and the bodies behind them¶

EN16931: The European semantic standard for a core electronic invoice — the data model and the business rules, with no mention of XML. "Compliant with EN16931" means a document carries the right information and obeys the rules; it says nothing about syntax. Published by CEN. The thing everything else on these pages specialises or implements. See the Overview.
CEN: Comité Européen de Normalisation — the European standards body that publishes EN16931. (The "EN" in EN16931 = European Norm.)
Semantic model: A description of what information a document carries, independent of how it is written down. EN16931 is a semantic model; UBL and CII are two ways to write it.
Business Term (BT) / Business Group (BG): The numbered fields of the EN16931 semantic model. BT-1 is "Invoice number", BT-24 is "Specification identifier", BG-4 is "Seller" (a group of related BTs). A syntax binding maps each BT/BG to a concrete element. See Anatomy of a UBL invoice.

Syntaxes — how the model is written as XML¶

Syntax / syntax binding: A concrete XML vocabulary that carries an EN16931 invoice, plus the mapping from each business term to an element. EN16931 has two official bindings.
UBL: Universal Business Language (OASIS). One of the two XML syntaxes; documents are rooted at <Invoice> and use the cbc:/cac: namespaces. The syntax used in most examples on this site. See Anatomy of a UBL invoice.
CII: Cross Industry Invoice (UN/CEFACT). The other XML syntax, using rsm:/ram: namespaces. Carries the same business terms as UBL — different element names, identical meaning. Why EN16931's rules are written as abstract patterns bound twice.
cbc / cac: The two UBL namespaces you see on nearly every element. cbc (CommonBasicComponents) = leaf fields that hold a single value; cac (CommonAggregateComponents) = containers that hold other elements. Mnemonic: cbc is a value, cac is a box.

Profiles — narrowing the core for real networks¶

Peppol: A cross-border network for exchanging business documents (invoices, orders, etc.), governed by OpenPeppol. Originally "Pan-European Public Procurement OnLine". More than a format — it is a network with registered participants and transport rules. See Peppol and CIUS profiles.
Peppol BIS: Business Interoperability Specification — Peppol's published profile documents. Peppol BIS Billing 3.0 is the invoicing one: a CIUS of EN16931 that says exactly how to fill in a UBL (or CII) invoice for exchange over Peppol. So "Peppol BIS" ≈ "the Peppol rulebook for this document type." Despite the intimidating name, it is just EN16931, narrowed, plus a handful of network-specific rules.
CIUS: Core Invoice Usage Specification — a profile that narrows EN16931: it can make optional fields mandatory or restrict code lists, but cannot add new business terms. Because it only narrows, every CIUS document is still a valid EN16931 document. Peppol BIS Billing 3.0 is a CIUS. See CIUS vs extension.
Extension: The other way to specialise EN16931: it may add new business terms beyond the core. More powerful than a CIUS, but the result is no longer fully readable by a plain EN16931 receiver.
CustomizationID (BT-24) / ProfileID (BT-23): The two fields by which an invoice declares which rulebook and process it follows. CustomizationID names the specification (plain EN16931, or a Peppol URN); ProfileID names the business process. See how an invoice declares its profile.

Validation¶

Schematron: A rule-based XML validation language: assertions of the form "in this context, this must be true." EN16931's business rules ship as Schematron. It compiles to XSLT to run. Full treatment in the Schematron section.
Business rule (BR-*): A numbered EN16931 rule, e.g. BR-01 ("an invoice shall have a specification identifier") or BR-CO-10 (an arithmetic total check). Distributed as public Schematron. The CO family are calculation rules.
SVRL: Schematron Validation Report Language — the XML report a Schematron run produces, listing which assertions fired, with what severity and message. When an invoice is "rejected by validation", the SVRL names the exact rule. See the pipeline.
XSD: XML Schema Definition — the grammar layer that checks structure and datatypes (is this element allowed here, is this a valid date). Runs before Schematron; catches different errors. See the XSD section.

Code lists¶

Code list: A controlled set of allowed values for a coded field — currencies, country codes, invoice-type codes. A coded field is only valid if its value is in the right list. See Genericode code lists.
Genericode (.gc): The OASIS file format that expresses a code list as data: a typed table with a key column and one row per code. EN16931 ships its lists as .gc files. See Genericode code lists.
UNCL: United Nations Code List — UN/EDIFACT-derived lists used by EN16931, each with a number: UNCL1001 (invoice type codes), UNCL5305 (VAT category codes), UNCL4461 (payment means). The number identifies which list.
ISO 4217 / ISO 3166 / UN/ECE Rec 20: The external standards behind common lists: ISO 4217 = currency codes (EUR), ISO 3166-1 = country codes (FI), UN/ECE Recommendation 20 = units of measure (C62 = "one/piece").

Identifiers and the network¶

Electronic address (EndpointID): The routable identifier of a party on the network — who to deliver to. Peppol requires it (cbc:EndpointID) though plain EN16931 does not. See what Peppol adds.
EAS / ICD: Code lists of identifier schemes. EAS (Electronic Address Scheme) says what kind of electronic address an EndpointID is; ICD (International Code Designator) does the same for organisation identifiers. The schemeID attribute on an identifier names which scheme it belongs to.
Four-corner model: Peppol's delivery architecture: sender (corner 1) → sender's Access Point (2) → receiver's Access Point (3) → receiver (4). The two middle corners are service providers; the addressing in the document is what lets them route it.
Access Point / SMP / SML: The Peppol transport machinery. An Access Point sends and receives on a participant's behalf; the SMP (Service Metadata Publisher) records what a participant can receive and where; the SML (Service Metadata Locator) is the network-wide directory that points to the right SMP. Transport-layer detail, outside the document itself.
KoSIT: The German public-IT coordination body that maintains the widely-used reference validator for EN16931 — the bundle of Schematron rules and .gc code lists much of the open-source tooling is built on.

Back to the section¶

Return to the Overview, or jump to Anatomy of a UBL invoice to see these terms on a real document.