UID

UID may refer to:

Identifying numbers

 * Unique identifier and instances or systems thereof

In computing

 * Unique identifier for a specific user of a computer system
 * Unique ID for the Mifare series of chips (integrated circuits) used in contactless smart cards and proximity cards.
 * Unique ID of a message in a folder on an IMAP server
 * User identifier (Unix), a code identifying each user on a Unix and Unix-like systems
 * Globally unique identifier (GUID)
 * Universally unique identifier (UUID)

In other areas

 * PubMed 'Unique Identifier' parameter (PMID) designating specific scientific publication abstracts (PubMed § PubMed identifier)
 * 'Unique Item Identifier', a specific value in the IUID (Item Unique Identification) system used by the United States Department of Defense for the identification of accountable equipment according to DoD Instruction 5000.64
 * Aadhaar number, originally the Unique Identification Number, an initiative of the Unique Identification Authority of India (UIDAI) of the Indian government to create a unique ID for every Indian resident
 * uID Center, a nonprofit organization in Tokyo, Japan, responsible for the Ucode system for uniquely identifying real-world objects electronically
 * German for: "UID = Umsatzsteuer Identifikation" (English: VAT identification number, VAT = value-added tax)

Organizations

 * Ulster Institute for the Deaf
 * Umeå Institute of Design
 * Unitedworld Institute of Design, college in India

Other uses

 * Unidentified decedent, a deceased person whose body has not yet been identified
 * Unintelligent Design, a satirical reaction to the Intelligent Design movement
 * Unit Identification, an LED used as a means of locating a specific computer server in a server room
 * Universal Instructional Design, an educational method that tries to deliver teaching to meet the needs of wide variety of learners
 * User interface design, device design with the focus on the user's experience and interaction