A is an attribute that may have one of several possible values for a particular . If a particular is applied to a , the resulting represents a more tightly defined of that .
Example: It might be possible to qualify a disorder such as according to its clinical course ( or ) or severity ("mild," "moderate" or ). With appropriate , "injury of skin of the left side of face" could then be represented even if a single cannot express this.
A similar tightening of the definition of a can be achieved by allowing one or more of the associated with a to be refined. A is refined by an that applies a specified of the value stated in the definition.
Example: could be refined by qualifying it with the finding site"tibia" to represent the .