greg

The root greg comes from Latin grex (genitive gregis), meaning a flock of sheep or a herd of cattle. Picture a Roman shepherd watching a hundred sheep cross a field — a single moving mass where no animal strays far from the rest. That image of the group, and of belonging to it or leaving it, is the seed of every greg word.

Latin attached prefixes to gregāre ("to flock together") to describe what happens to the flock:

- con- (together) + greg → congregate: drive the flock together into one place. People congregate; in churches the assembled flock became the congregation — a beautiful survival of the shepherd metaphor, with the priest as shepherd (pastor literally means "shepherd") tending his human flock.
- se- (apart, aside) + greg → segregate: cut animals away from the flock. The word kept its harshest edge in human history — racial segregation is the forced separation of one group from another.
- ad- (to, toward) + greg → aggregate / aggregation: add things to the flock until they pile into one mass. In modern English it means to gather many small parts into a total — a news aggregator pulls many stories into one feed.
- e-/ex- (out of) + greg → egregious: literally "standing out of the flock." Here is the family's surprise. In classical Latin egregius was a compliment — to rise above the common herd was to be distinguished, excellent. But English speakers used it sarcastically — "oh, an egregious example" — so often that the irony hardened into the literal meaning. Today egregious means outstandingly bad, shockingly wrong. The word that once praised you now condemns you.

And the most literal of all: gregarious = "living in a flock." Zoologists still use it for herd animals, but for people it means sociable, flock-loving — someone who, like a sheep, is happiest in the middle of the group.

The pattern is clean: the root greg always means the flock; the prefix tells you whether you're gathering it (con-), splitting it (se-), piling onto it (ad-), or stepping out of it (e-).