Definition of diagnostic
(Entry 1 of 2)
1a
: of, relating to, or used in diagnosis
a diagnostic tool
b
: using the methods of or yielding a diagnosis
diagnostic tests
2
: serving to distinguish or identify
a diagnostic feature
diagnostic
nounDefinition of diagnostic (Entry 2 of 2)
1
: the art or practice of diagnosis
—often used in plural
2
: a distinguishing mark
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Merriam-Webster unabridged
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Time Traveler for diagnostic
The first known use of diagnostic was in 1625
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