The Gregorian Mode is a musical mode used in chants of the Western Church, especially in the Middle Ages. This particular mode has acquired synonyms due to various factors. One of which is the regional difference, as it is known as the "Lydian-mode" in the Eastern Church. Other synonyms include the "Plagal-mode" and "Authentic-mode," which represents the different tonalities of a single mode. Another synonym is the "Church-mode" since the Gregorian chants are also referred to as the "plainchant," which is a type of monophonic music that is sung in unison. Additionally, it is also known as the "Canto-manuscript" as music was recorded in manuscripts during this era. The use of these synonyms adds depth and variety in describing this musical mode and its historical significance.