di·a·tes·sa·ron 
(dī′ə-tĕsər-ən)
(dī′ə-tĕsər-ən)n.
The four Gospels combined into a single narrative.
[Middle English, interval of a fourth, from Latin diatessarōn, made of four, from Greek dia tessarōn, out of four : dia, according to; see DIA- + tessarōn, genitive of tessares, four; see kwetwer- in the Appendix of Indo-European roots.]