diagnostic
adjective
[ dʌɪəɡˈnɒstɪk ]
• concerned with the diagnosis of illness or other problems.
• "a diagnostic tool"
• characteristic of a particular species, genus, or phenomenon.
• "the diagnostic character of having not one but two pairs of antennae"
diagnostic
noun
• a distinctive symptom or characteristic.
• the practice or techniques of diagnosis.
• "advanced medical diagnostics"
Origin:
early 17th century: from Greek diagnōstikos ‘able to distinguish’, from diagignōskein ‘distinguish’; the noun from hē diagnōstikē tekhnē ‘the art of distinguishing (disease)’.