Other forms: diagnostics
A diagnostic is a test that finds where a fault lies. Run a diagnostic, the diagnostic showed, diagnostic tools.
In cars and computers a diagnostic reads codes from the system and points at the failing part, which turns guessing into looking. In medicine, diagnostic tests are those that establish what is wrong, as against screening tests, which look at people with no symptoms — the distinction matters because the same test performs differently in the two roles. Note diagnosis, diagnose; and diagnostic of, meaning characteristic of.
1noundiagnosticA test that finds where a fault lies.
“The mechanic ran a diagnostic on the car's computer to find the fault.”
2adjectiveservingServing to identify what is wrong.
“The doctor ordered diagnostic tests to find out why she was always so tired.”
diagnostic is an identifying test.
Greek diagnostikos comes from diagignoskein, to distinguish — dia, apart, plus gignoskein, to know. Know, gnosis and prognosis come from the same knowing.
Ancient Greek
δῐαγνωστῐκός
English, today
diagnostic
Built from
Borrowed from Ancient Greek δῐαγνωστῐκός. From Ancient Greek διαγνωστικός, adjective from διαγιγνώσκω (“to distinguish, diagnose”).
Etymology from Wiktionary, CC BY-SA
Practised in Repair & Damage