Meaning & use
polygraph
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Meanings
nouncountable
A machine that measures changes in a person's body, such as heart rate and breathing, often used to try to detect lies.
Grammar: Countable; can be used with 'a' or in the plural.
Patterns
- take a polygraph test
- pass/fail a polygraph
- use a polygraph on someone
The suspect agreed to take a polygraph test.
Polygraphs are not admissible as evidence in many courts.
She was asked to undergo a polygraph examination during the investigation.
nouncountabletechnical
A device that makes a continuous record of several body functions, used in medical or scientific settings.
Grammar: Technical sense; less common in everyday speech.
Patterns
- polygraph recording
- polygraph machine
The polygraph recorded the patient's breathing and pulse during sleep.
Researchers used a polygraph to monitor physiological responses.
The old polygraph in the lab still works perfectly.
Word forms
| plural | polygraphs |
|---|
Common combinations
- polygraph test
- He was nervous about the polygraph test.
- polygraph examination
- The polygraph examination lasted over an hour.
- polygraph results
- Polygraph results are not always reliable.
- take a polygraph
- She refused to take a polygraph.
- polygraph machine
- The polygraph machine printed a long sheet of paper.
Synonyms and how they differ
- lie detector
- Everyday term for the same device; 'polygraph' is more formal and technical.
Word family
- polygraphic adjective
- Relating to a polygraph or to the recording of multiple signals.
Commonly confused: polygraph or paragraph? polygraph or polygraphy?
polygraph vs paragraph
A paragraph is a section of writing; a polygraph is a lie-detector machine. They sound similar but are unrelated.
polygraph vs polygraphy
Polygraphy can mean the study or use of polygraphs, but it is rare; the device itself is a polygraph.
Practice
Which sentence uses 'polygraph' correctly?
Choose one answer.
A polygraph is a machine that records physical changes like heart rate and breathing. Option 1 confuses it with 'paragraph'. Option 2 confuses it with 'polyglot'. Option 3 confuses it with a cutting tool.
Make it your own
Write a sentence using “polygraph”, then check it and compare it with the examples above.