polygraph

noun

poly·graph ˈpä-lē-ˌgraf

: an instrument for recording variations of several different pulsations (as of physiological variables) simultaneously compare lie detector

polygraphic

ˌpä-lē-ˈgra-fik

adjective

Did you know?

With its graph- root, polygraph indicates that it writes out several different results. A polygraph's output consists of a set of squiggly lines on a computer screen, each indicating one function being tested. The functions most commonly measured are blood pressure, breathing rate, pulse, and perspiration, all of which tend to increase when you lie. Polygraphs have been in use since 1924, and have gotten more sensitive over the years, though many experts still believe that they're unreliable and that a prepared liar can fool the machine. They're used not only for law enforcement but perhaps more often by employers--often the police department itself!--who don't want to hire someone who has broken the law in the past but won't admit to it.

Example Sentences

They hooked him up to the polygraph and began the test. She was asked to take a polygraph.

Recent Examples on the Web Acosta also found that Gable’s conviction resulted from improper interrogation of witnesses by investigators and flawed polygraphs that further shaped witness statements to police. —

oregonlive, 8 May 2023 However, there is significant uncertainty around the efficacy of polygraphs, as these physiological changes can also be produced by states other than lying. —

Conor Feehly, Discover Magazine, 14 Apr. 2023 Like that time, the National Gym Association in Coconut Creek will sanction the contest, providing judges, drug testing, polygraphs and the like. —

Rod Stafford Hagwood, Sun Sentinel, 10 Apr. 2023 Episodes include new details about the cases, dramatic polygraph audio with the deputy and exclusive interviews with lead investigators, media mogul Tyler Perry, famous civil rights attorney Ben Crump, the parents of Terrance Williams and advocates for Felipe Santos. —

USA Today, 4 Apr. 2023 Thursday also featured polygrapher and attorney Lawrence Beaumont, who discussed the results of the polygraph tests Van Allen and Murrell took. —

Althea Legaspi, Rolling Stone, 25 Aug. 2022 The parents agreed to take the polygraph test — often referred to as a lie detector test — to help detectives focus their search on other tips, Pamela Allen, CEO of Eagles Flight Advocacy and a close family friend, said Friday. —

Jacob Beltran, San Antonio Express-News, 21 Apr. 2023 Investigators in previous leak investigations have been known to use polygraph tests to help determine the truthfulness of people being interviewed for the investigation. —

Luis Martinez, ABC News, 7 Apr. 2023 Developer and former lawmaker Chris Dorworth voluntarily took a polygraph exam last September, seeking to refute allegations made by former Seminole Tax Collector Joel Greenberg in a jailhouse interview over the summer. —

Annie Martin, Orlando Sentinel, 24 Jan. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'polygraph.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

borrowed from French polygraphe, from poly- poly- + -graphe -graph

Note: As a word for such an instrument, polygraphe was apparently introduced by the French physiologist and inventor Étienne-Jules Maret (1830-1904). Compare "Des appareils enregistreurs en biologie," part 6 of "Histoire naturelle des corps organisés," Revue des cours scientifiques de la France et de l'étranger, 4. annéee (1867), p. 695: "Je vais mettre sous vos yeux l'enregistreur perfectionné que j'emploie aujourd'hui dans un grand nombre de circonstances. J'appelle polygraphe cet appareil, qui peut fournir le graphique d'un grand nombre de phénomènes différents." ("I am going to place before your eyes a perfected recording device that I have used in a great number of situations. I am calling this device a polygraph, which can provide a graphic record of a great number of different phenomena.") The word polygraph had been used earlier in English for a voluminous or versatile writer (after Greek polýgraphos "writing much"), an imitator, and an instrument resembling a pantograph.

First Known Use

1871, in the meaning defined above

Time Traveler

The first known use of polygraph was in 1871

See more words from the same year

Cite this Entry

Style

“Polygraph.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/polygraph. Accessed 28 May. 2023.

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Kids Definition

polygraph

noun

poly·graph ˈpäl-i-ˌgraf

: an instrument for recording changes in several bodily functions (as blood pressure and rate of breathing) at the same time

compare lie detector

Medical Definition

polygraph

noun

poly·graph ˈpäl-i-ˌgraf

: an instrument for simultaneously recording variations of several different pulsations (as of the pulse, blood pressure, and respiration) see lie detector

polygraphic

ˌpäl-i-ˈgraf-ik

adjective

polygraphically

-i-k(ə-)lē

adverb