Definition of "polygraph"

polygraph

/ˈpɒliɡɹæf/

noun
plural polygraphs
1. A device which measures and records several physiological variables such as blood pressure, heart rate, respiration and skin conductivity while a series of questions is being asked to a subject, in an attempt to detect lies.
2. (dated) A mechanical instrument for multiplying copies of a writing, resembling multiple pantographs.
3. (archaic) A collection of different works, either by one or several authors.
4. (linguistics) A group of letters that represent a single phoneme.
5. Any group of letters treated as a single item.
  Quotations
  A polygraph consists of an unspecified number of adjacent letters. A polygraph need not be recognisable as a word in a language but if we are attempting to decipher a message which is expected to be in English and we find the heptagraph MEETING it is much more promising than if we find a heptagraph such as DKRPIGX.
  2002, Robert Churchhouse, Codes and Ciphers: Julius Caesar, the Enigma, and the Internet, page 3
6. An author who writes on many subjects.
7. (mathematics) A multidimensional directed graph; a computad.
verb
third-person singular simple present polygraphs, present participle polygraphing, simple past and past participle polygraphed
1. (transitive) To administer a polygraph test to.