polygraph

poly- +‎ -graph

• IPA^(key): /ˈpɒliɡɹæf/, /ˈpɒliɡɹɑːf/

• Audio (Southern England)

  (file)

• Rhymes: -æf, -ɑːf

polygraph (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.

   Synonym: lie detector

2. (dated) A mechanical instrument for multiplying copies of a writing, resembling multiple pantographs.

   Synonyms: manifold writer, autopen

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.
   • 2002, Robert Churchhouse, Codes and Ciphers: Julius Caesar, the Enigma, and the Internet, page 3:

     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.

6. An author who writes on many subjects.
7. (mathematics) A multidimensional directed graph; a computad.

polygraph (third-person singular simple present polygraphs, present participle polygraphing, simple past and past participle polygraphed)

1. (transitive) To administer a polygraph test to.

   The FBI polygraphed the suspect but learned nothing because they already knew he was lying.

• truth serum
• digraph, trigraph