A group of related material within a series, usually identified by subject, type of material, function, or filing arrangement.

A series which appears as part of a numbered series (main series). The subseries may or may not have a title dependent on that of the main series. See also Common title, Dependent title, Section (Serials). * NOTE: THIS DEFINITION IS REVISED -- Cf . p. 623 of AACR2R. ALSO, in AACR2R subseries is not hyphenated.

A series or serial within a series (i.e., a series or serial that always appears in conjunction with another, usually more comprehensive, series of which it forms a section). Its title may or may not be dependent on the title of the main series. See also Section.