adjective

1. of or constituting a diagnosis
2. of value for a diagnosis; specif., characteristic
3. Comput. of or having to do with the use of computer diagnostics

Etymology: ML diagnosticus < Gr diagnōstikos

noun

1. the art, science, or method of diagnosis, esp. medical diagnosis
2. a distinguishing sign or symptom; characteristic
3. Comput. a routine for testing a piece of hardware or for locating an error in a program