600 Subfield $v - Form subdivision:

Subfield $v contains a form subdivision that designates a specific kind or genre of material as defined by the thesaurus being used. Subfield $v is appropriate only when a form subject subdivision is added to a personal or family name to form an extended subject heading. Subfield $v is used for form terms when they function as indicated above. Subfield $x may be used if the terms function as general subdivisions. A form subdivision in subfield $v is generally the last subfield in the field. The subfield may be repeated if more than one form subdivision is used.

Examples:

600 3#$aClark family$vFiction.

600 0#$aGautama Buddha$vBiography$vEarly works to 1800.