The word egregore comes from the Greek ἑγρήγορος egrḗgoros meaning “wakeful” or “watching”.
The egregore or egregor is a term used by members of the Hermetic Order of the Golden Dawn and The Kabalistic Order of Rosicrucians to describe the personality a group takes on independent of its members. It is a sort of thought form being that is formed from the collective consciousness of a group of people but develops its own autonomy capable of exerting influence on the group’s members.
Groups can put conscious work and thought into creating an egregore, but when groups work toward collective ideal long enough, it takes on a life of its own.
In Abrahamic tradition, the Egregor or Grigori, are the Watchers, a group of angels mentioned in the Book of Enoch and by Elphias Levi in Le Grand Arcane