link:usedOn 

Definition of the usedOn element - used
to identify what elements may use a 
taxonomy defined role or arc role value.

Element Information

Model

Used By

Elements link:arcroleType, link:roleType

Source 

<element name="usedOn" type="QName">
  <annotation>
    <documentation>Definition of the usedOn element - used to identify what elements may use a taxonomy defined role or arc role value.</documentation>
  </annotation>
</element>

Sample