English Reference

Word

diagnostic

Phoneticsdi·ag·nos·tic

US/ˌdaɪəɡˈnɑstɪk/

UK/dˌaɪəɡnˈɒstɪk/

Definitions

01medical/technical identification

B2 · Medicine

adj. used to help identify a disease or a technical problem.

adj. relating to or used in the identification of a medical condition or a technical malfunction.

“The doctor ordered a diagnostic test to see why the patient was feeling dizzy.”

“The hospital invested in advanced diagnostic imaging equipment to improve the accuracy of early-stage cancer detection.”

Technical

Usage

Often modifies nouns like 'test', 'tool', or 'procedure'.

02educational assessment

B2 · Education

adj. a test given at the start of a course to see what you already know.

adj. designed to assess a learner's strengths, weaknesses, and prior knowledge before instruction begins.

“We took a diagnostic quiz on the first day of the Spanish class.”

“The diagnostic assessment revealed that while the students had strong vocabulary skills, they struggled significantly with complex grammatical structures.”

Academic

Synonyms

pre-assessment

03a tool or test

C1 · Computing

n. a specific test or program used to find a fault or problem.

n. a procedure, program, or tool used to identify the cause of a problem or the nature of a condition.

“The mechanic ran a diagnostic on the car's engine to find the leak.”

“After the system crash, the IT department ran a full suite of diagnostics to determine if the failure was hardware-related or a software bug.”

Technical

Usage

Frequently used in the plural form 'diagnostics' when referring to computer routines.

Synonyms

Real-World Examples

“Improving accuracy is important because the average human error rates involving diagnostic images are estimated to range from 3 to 5 percent, which translates to about 40 million errors worldwide each year .”
Smithsonian Magazine · 29 Jul 2026
“If you do, then this, like other diagnostic tests in the public system, will be free.”
The Local · 13 Aug 2026

Etymology

From Ancient Greek διαγνωστικός (diagnōstikós), adjective from διαγιγνώσκω (diagignṓskō, “to distinguish, diagnose”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Collocations

diagnostic capacity

Word family

diagnoseVerbdiagnosisNoundiagnosticAdjective

Domains

BiologyComputingEducationMedicine

This entry

Level
B2 · Upper Intermediate
Frequency
Frequent
Updated

Scan code

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English Reference