A subset S of a field F is a subfield if it contains 0 and 1, and is closed under subtraction and multiplication and inverses, i.e. if x is in S and is not zero, then x-1 is in S.
A segment within a field of a bibliographic record designed for particular content. For example, the title proper is in the $a subfield of the 245 field, the other title information or subtitle is in the $b of that field, and the statement of responsiblitity is in the $c of the 245 field.
Part of a field that is subdivided - for example, for titles and subtitles, or place of publication and publisher.
Each type of data within a field.
The smallest logical unit of information in a variable field. Subfield codes (letters or numbers) identify subfields and are preceded by a delimiter (‡). A subfield ‡ a is implicit at the beginning of most fields, but does not display. See also delimiter.
A subdivision of a MARC field; subfields are usually identified by letter and contain specific information related to a particular tag (ex. 245 #a, 245 #b, etc.).
A subdivision of a variable field containing data logically identifiable as a discrete unit of that field. A typical personal name field, for example, has a subfield for the name itself, plus (if applicable) subfields for birth and death dates, titles of distinction associated with the name, fuller forms of the name, etc. The subfield “a†at the beginning of a field does not display in many systems.
A subdivision of a variable field containing data logically identifiable as a discrete unit of that field. A typical publication field, for example, has three subfields: place, publisher, and date. Except for subfield "a" at the beginning of a field, each subfield is proceeded by a delimiter ( ‡ ) and a subfield code.
