Definition of polygraph

• n. - An instrument for multiplying copies of a writing; a manifold writer; a copying machine.
• n. - In bibliography, a collection of different works, either by one or several authors.
• n. - An instrument for detecting deceptive statements by a subject, by measuring several physiological states of the subject, such as pulse, heartbeat, and sweating. The instrument records these parameters on a strip of paper while the subject is asked questions designed to elicit emotional responses when the subject tries to deceive the interrogator. Also called lie detector