A keyword is a finding aid used to record one subject term, key phrase, abbreviation, indexing word, taxonomic structure, or other expression that is associated with the whole structure (such as an article). Keywords can be used for identification, searching, and indexing purposes. A keyword element (<kwd>) may contain a repetition of words found in the structure or it may contain broader terms, narrower terms, related terms, or taxonomic identifiers used to find the structure in a search or provide semantic classification of the text by mapping a specific structure to a taxonomy.
Any combination of:
Text, numbers, or special characters
Emphasis Elements
Baseline Change Elements