1. A harmony of the four Gospels (Matthew, Mark, Luke, and John) into a single continuous narrative.
Usage: religious/theological; historical
2. In music, an interval spanning four diatonic scale degrees; a perfect fourth.
Usage: music theory; archaic or technical

Examples

• Tatian's Diatessaron was one of the earliest attempts to create a unified Gospel narrative.
• The Diatessaron combined all four Gospel accounts into a single coherent story.
• Medieval scholars studied the Diatessaron to understand how the Gospels relate to one another.
• In early Christian tradition, the Diatessaron was sometimes preferred over the separate Gospels.
• The musical interval of a diatessaron, or perfect fourth, is fundamental to Western harmony.