polygraph

American  

[pol-i-graf, -grahf] / ˈpɒl ɪˌgræf, -ˌgrɑf /

noun

1. an instrument for receiving and recording simultaneously tracings of variations in certain body activities.

2. a test using such an instrument to determine if a person is telling the truth.

3. lie detector.

4. an apparatus for producing copies of a drawing or writing.

5. a prolific or versatile author.

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verb (used with object)

1. to test (a person) with a polygraph.

polygraph British  

/ -ˌɡræf, ˌpɒlɪˈɡræfɪk, ˈpɒlɪˌɡrɑːf /

noun

1. an instrument for the simultaneous electrical or mechanical recording of several involuntary physiological activities, including blood pressure, skin resistivity, pulse rate, respiration, and sweating, used esp as a would-be lie detector

2. a device for producing copies of written, printed, or drawn matter

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Other Word Forms

• polygrapher noun
• polygraphic adjective
• polygraphically adverb
• polygraphist noun

Etymology

Origin of polygraph

1795–1805 polygraph for def. 1; 1920–25 polygraph for def. 3; < Greek polýgraphos writing much. See poly-, -graph

Example Sentences

When the detective asked her to take a polygraph, she consented.

From Slate • Apr. 6, 2026

“I’m willing to take a polygraph test to make this stop,” she said.

From The Wall Street Journal • Mar. 15, 2026

Perez requested a polygraph test and failed it, Flores testified.

From Los Angeles Times • Feb. 19, 2026

Kruger had noted a link between failed polygraph tests on its rangers and a surge in poaching, with follow-up investigations resulting in the dismissal of seven staff, it said.

From Barron's • Feb. 10, 2026

Lie-detection tests are notoriously inaccurate, and calculations similar to the above demonstrate why truthful people who flunk polygraph tests usually outnumber liars.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos