Terms, explained briefly

The vocabulary that turns up in quotes, invoices and interfaces — without the marketing spin.

Core concepts

ERP: Enterprise resource planning. Software that runs a company's operational resources in one system — orders, inventory, purchasing, accounting and staff, instead of a separate program for each.
CRM: Customer relationship management. Managing contacts, prospects and customers along with all communication with them — who said what and when, and what came of it.
Order management: An order's path from enquiry through quote, execution and delivery to invoice. In software that path is represented as a sequence of statuses.
Multitenancy: A system's ability to run several customers separately from one another. The separation can be logical (shared tables with a tenant column) or physical, with a dedicated database per customer.
White-label: Running software under someone else's name and appearance — their logo, colours, domain and, if wanted, their own product name.

Quote: A binding price offer to a customer, usually with a validity date. If the customer accepts, it becomes an order.
Order confirmation: Written confirmation that an order has come about, with the agreed scope and price. It records what was actually commissioned.
Delivery note: The document recording a handover of goods. It lists the delivered items and quantities, but no prices.
Service report: Documentation of work performed on site — what was done, how long it took and what material was used. Often countersigned by the customer.
Costing: Working out the selling price from cost plus markup. It shows what margin a line item actually carries.
Dunning: The staged process of chasing unpaid invoices — from a payment reminder through formal dunning levels to dunning fees and default interest.

VAT identification number: The VAT identification number that uniquely identifies a business in the EU single market. It is a precondition for tax-free intra-Community supplies.
Reverse charge: A reversal of the tax liability: the recipient rather than the supplier owes the VAT. The invoice is issued without VAT and must say so.
Small business scheme: A VAT exemption for businesses below a turnover threshold. Invoices are issued without VAT; in return, input tax cannot be deducted.
Intra-Community supply: A supply of goods to a business in another EU member state. Under certain conditions it is exempt from VAT, among them a valid VAT number for the recipient.
GDPR: The EU General Data Protection Regulation. It governs the conditions under which personal data may be processed and what rights the people concerned have.
Data processing agreement (DPA): The contract required under Art. 28 GDPR between controller and processor. It sets out the subject matter, duration, nature and purpose of the processing, plus the technical and organisational measures.

REST API: A programming interface other systems can read and write data through — over HTTP, usually in JSON. It is how one piece of software is connected to another.
Idempotency: The property that repeating a call produces the same result as the first one. In interfaces it prevents a call retried after a network error from creating a record a second time.
DATANORM: An exchange format widespread in German-speaking countries for article master data between wholesalers and trades. It supplies article numbers, descriptions, prices and discount groups in one uniform structure.
GTIN / EAN: The globally unique article number behind a barcode. GTIN is the current name; EAN was the earlier European one.
SKU: Stock keeping unit — a company's internal article number. Unlike a GTIN it is assigned by the business itself and only has to be unique internally.
Two-factor authentication (2FA): A sign-in that requires a second proof alongside the password — for example a time-limited code from an app. A stolen password alone is then no longer enough.