origin
English: from a personal name that was popular throughout Christendom in the Middle Ages. The Greek original, Gregorios, is a derivative of gregorein ‘to be awake’, ‘to be watchful’. However, the Latin form, Gregorius, came to be associated by folk etymology with grex, gregis, ‘flock’, ‘herd’, under the influence of the Christian image of the good shepherd.
The Greek name was borne in the early Christian centuries by two fathers of the Orthodox Church, St. Gregory Nazianzene (c. 325–390) and St. Gregory of Nyssa (c. 331–395), and later by sixteen popes, starting with Gregory the Great (c. 540–604). It was also the name of 3rd- and 4th-century apostles of Armenia.
In North America the English form of the name has absorbed many cognates from other European languages.