| Subject | Welsh | English |
| comp., MS | e-bost fel ID mewngofnodi | e-mail as sign in ID (A Windows Live ID created in a domain, and using the domain name, before the domain was enrolled in Outlook Live. After the Windows Live ID is imported into the Outlook Live domain, it is subject to the security and privacy policies of the organization) |
| comp., MS | ID digidol | Digital ID (A combination of a digital certificate and a public and private encryption key set) |
| comp., MS | ID digyfnewid | immutable ID (A unique user identifier that must not change for the user over the lifetime of the user being in the system) |
| comp., MS | ID diogelwch | security ID (In Windows-based systems, a unique value that identifies a user, group, or computer account within an enterprise. Every account is issued a SID when it is created) |
| comp., MS | ID Dogfen | Document ID (A unique, persistent identifier assigned to a document or other item in SharePoint Server that allows it to be referenced and retrieved regardless of its location) |
| comp., MS | ID dosbarth | class ID (A universally unique identifier (UUID) that identifies a COM component. Each COM component has its CLSID in the Windows registry so that it can be loaded by other applications) |
| comp., MS | ID dosbarthu | dispatch ID (A 32-bit integer that identifies a property set) |
| comp., MS | ID Dyblyg | Replication ID (A 16-byte value generated from the unique identifier on a device, the current date and time, and a sequence number. It is used to identify a particular device, component, user, or session) |
| comp., MS | ID eithrio | exempt ID (An identification number that is issued by a tax authority to indicate that a company is not required to pay sales tax) |
| comp., MS | ID hysbysebu | advertising ID (An identifier used by app developers and advertising networks to provide more relevant advertising to users by understanding which apps they use and how they use them) |
| comp., MS | ID Iaith | Language ID (A standard international numeric abbreviation for a country or geographical region. A language identifier is a 16-bit value that consists of a primary language identifier and a secondary language identifier) |
| comp., MS | ID Locale | locale ID (A 32-bit value which consists of the language ID in the low word (bits 0-15) and the sorting ID (bits 16-19) and a reserved value (bits 20-31) in the high word) |
| comp., MS | id pryniant | purchaseid (A unique code used to identify a purchase for transaction tracking and billing purposes) |
| comp., MS | ID TAW | VAT ID (A unique number governments issue to companies and citizens in order to track taxes paid on goods and services. VAT IDs in the European Union contain a country prefix followed by up to 12 digits or characters) |
| comp., MS | URL Canfod ID Dogfen | Document ID Lookup URL (A URL that is based on a query using the Document ID rather than the physical location of the item) |