• PDFA file format developed by Adobe Systems that provides hardwareand software-independent viewing of a formatted document.
  • permuted displayA type of index where individual words of a term are rotated to bring each word of the term into alphabetical order in the term list. See also KWIC and KWOC.
  • pick listA graphical user interface device that allows the user to select from a pre-set list of terms. Typically the list of terms is shown when the user clicks on a down arrow next to the entry box for the term.
  • polyhierarchyA controlled vocabulary structure in which some terms belong to more than one hierarchy. For example, rose might be a narrower term under both flowers and perennials in a horticulture vocabulary.
  • polysemeA word with multiple meanings. In spoken language, polysemes are called homonyms; in written language they are called homographs. Only the latter are relevant to controlled vocabularies designed for textual information.
  • postcoordinationThe combining of terms at the searching stage rather than at the subject heading list construction stage or indexing stage. See also precoordination.
  • postingsThe number of content objects to which a term is assigned.
  • precisionA measure of a search system's ability to retrieve only relevant content objects. Usually expressed as a percentage calculated by dividing the number of retrieved relevant content objects by the total number of content objects retrieved. A high-precision search ensures that, for the most part, ...
  • precoordinationThe formulation of a multiword heading or the linking of a heading and subheadings to create a formally controlled, multi-element expression of a concept or object. Precoordination is often used to ensure logical sorting of related expressions. Examples of precoordinated headings: New England ...
  • preferred termOne of two or more synonyms or lexical variants selected as a term for inclusion in a controlled vocabulary. See also non-preferred term. NOTE: In the previous version of this Standard, a preferred term was known as a descriptor.