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

The person in question had no alibi for the night of the murder and had failed two polygraph tests, according to police records.

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

Castro was accused of being an agent of the CIA or of the US Drug Enforcement Agency and subjected to polygraph tests, during which the same set of questions was put to him for hours.

From Barron's • Feb. 6, 2026

Isaac also remembered what he called Jefferson’s “copyin’ machine,” or polygraph, which could automatically produce an exact copy of what Jefferson wrote with his own pen.

From "In the Shadow of Liberty" by Kenneth C. Davis