UID may refer to:
Unique identifier for a specific User of a computer system
User identifier (Unix), a code identifying each user on a Unix and Unix-like systems
User interface design, device design with the focus on the user's experience and interaction
Ulster Institute for the Deaf
Unintelligent Design, a satirical reaction to the Intelligent Design movement
PubMed 'Unique Identifier' parameter designating specific scientific publication abstracts; see PMID
'Unit IDentification light', a light found on all HP/Compaq DL servers that allows users to distinguish which server they are working on in a server rack
'Unique Item Identifier', a specific value in the Item Unique Identification system used by the United States Department of Defense for the identification of accountable equipment according to DoD Instruction 5000.64
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