(1) A format code used in a document language. See tagged text, HTML tag, character tag and paragraph tag.

(2) See RFID tag and smart tags.

(3) A set of bits or characters that identifies various conditions about data in a file and is often found in the header records of such files.

(4) A name (label, mnemonic) assigned to a data structure, such as a field, file or paragraph. See tagged text and XML.

(5) A descriptive field in a music or video file. See ID3 tag.

(6) The key field in a record.

(7) A brass pin on a terminal block that is connected to a wire by soldering or wire wrapping.