<compound-kwd> Compound Keyword

Wrapper element for multi-part keywords (for example, a code and its description/title/meaning).


When to Use Compound Keyword

Some keywords are a simple word or phrase; such keywords should generally be tagged using the <kwd> element. The <compound-kwd> element is used when keywords are composed of multiple parts, such as:
  • a code and its meaning, or
  • an abbreviation and its expansion.
Language in Keywords
Keywords are contained in <kwd-group> elements. There may be several <kwd-group>s, each of which can be identified separately by language, vocabulary, or taxonomy source. Since different languages could mean, for example, different writing directions, none of the individual keyword elements (<kwd>, <compound-kwd>, <nested-kwd>) take the @xml:lang attribute; that is reserved for the <kwd-group> element. This means that if there are keywords in several languages they should be in different <kwd-group>s.
Vocabulary Attributes
For controlled vocabularies, two attributes can be used to link a keyword to its term source:
  • @vocab-term — This attribute holds the canonical form of the keyword as expressed in the vocabulary named in the <kwd-group>. The content of the keyword element (<kwd>, <compound-kwd>, <nested-kwd>) might not be exactly the same as the canonical form, as the keyword element content might be a user-specific variant, for example, the term in another language.
  • @vocab-term-identifier — This attribute holds a unique identifier and possible pointer to the specific term in the named vocabulary (typically a URI or DOI reference), but @vocab-term-identifier could be an item number or other system-specific identifier.
Related Elements
Types of Keywords: This Tag Set contains several differently-structured types of keywords:
  • <kwd> Used with simple keywords, such as words or phrases.
  • <compound-kwd> Used with multi-part keywords, such as keywords that contain both a code and its expansion/description/name/title.
  • <nested-kwd> Used with hierarchical keyword structures, such as taxonomies, to record a portion of a taxonomic hierarchy. Both simple and compound keywords can be nested hierarchically.
Keywords vs Subjects Terms: Subject terms (collected within a <subj-group> element) name broad classifications, categories, topics, or themes that describe or classify a standard. Keywords (collected within a <kwd-group> element) contain words from the narrative text or words (such as broader and narrower terms) related to that text.

Base Attributes

Models and Context
May be contained in
Content Model
<!ELEMENT  compound-kwd %compound-kwd-model;                         >
Expanded Content Model


Tagged Sample

INSPEC keywords added by SDO

<kwd-group id="KG1" originator="ASME" vocab="Inspec"
 <compound-kwd id="KG1.1">
  <compound-kwd-part content-type="code">A7865P</compound-kwd-part>
  <compound-kwd-part content-type="text">Optical properties of other 
   inorganic semiconductors and insulators (thin films/low dimensional 

 <compound-kwd id="KG1.2">
  <compound-kwd-part content-type="code">A7865T</compound-kwd-part>
  <compound-kwd-part content-type="text">Optical properties of organic
   compounds and polymers (thin films/low dimensional structures)</compound-kwd-part>
Related Resources