Stellium

A stellium is three or more bodies gathered in one sign or one house, and some astrologers set the bar at four. The effect is concentration: that sign's style, or that house's affairs, takes up far more of the chart than usual, and the rest of the chart tends to be read through it. A stellium in a house marks a life area that draws repeated attention. A stellium in a sign marks a strongly colored temperament. The cost is everything the cluster does not cover, which gets less instinctive attention and often has to be handled deliberately.