Short form of Gregory, from Greek 'gregorios' meaning 'watchful' or 'alert.'
Greg is the short form of Gregory, which descends through Latin Gregorius from the Greek Grēgorios — itself derived from grēgorein, meaning to be awake, to be vigilant. It is a name that commands alertness and watchfulness, originally associated with the Christian concept of spiritual wakefulness, of souls attentive to God and to the needs of others. This etymology made it a natural choice for ecclesiastical leaders, and the list of popes who bore the name Gregory spans from the sixth century to the twentieth, with Gregory the Great (540–604 CE) being the most transformative — a pope who reshaped the Roman church, standardized its liturgy, and dispatched missions to England that Christianized the Anglo-Saxons.
Greg as a standalone given name, rather than a diminutive, belongs largely to the twentieth century, especially to mid-century American and British naming conventions where short, punchy names — Tom, Jim, Bob, Greg — were a statement of plainspoken unpretentiousness. It shares that era's democratic quality: approachable, direct, carrying no pretension. The name appeared widely in postwar American culture, borne by athletes, comedians, scientists, and ordinary people in equal measure.
Today Greg feels genuinely retro, belonging to a generation now in their fifties and sixties in much of the English-speaking world. This gives it a curious double valence: it can read as dated or, increasingly, as a kind of confident unfashionableness — a name that's too settled in itself to care about trends. In that sense it may be ripe for the generational revival that has already brought Max, Jack, and Sam back to nurseries, waiting for the cycle to turn.