polygraph

UK: /ˈpɒligrɑːf/ US: /ˈpɑlɪˌgræf/ ,(pol′i graf′, -gräf′)

WordReference Random House Learner's Dictionary of American English © 2025

pol•y•graph /ˈpɑlɪˌgræf/   n. [countable]

1. Medicine lie detector.
2. Medicine a test using a lie detector.

v. [~ + object]

3. Medicine to test (a person) with a polygraph.

See -graph-.

WordReference Random House Unabridged Dictionary of American English © 2025

pol•y•graph  (pol′i graf′, -gräf′), n. 

1. Medicine an instrument for receiving and recording simultaneously tracings of variations in certain body activities.
2. Medicine a test using such an instrument to determine if a person is telling the truth.
3. Medicine See lie detector. 
4. an apparatus for producing copies of a drawing or writing.
5. a prolific or versatile author.

v.t. 

6. Medicine to test (a person) with a polygraph.

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

pol•y•graph•ic  (pol′i graf′ik), adj.  po•lyg•ra•phist  (pə lig′rə fist), po•lyg′ra•pher, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

polygraph / ˈpɒlɪˌɡrɑːf -ˌɡræf/ 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

Etymology: 18th Century: from Greek polugraphos writing copiously