lodestarSee several planets gathered in one part of a birth chart? An astrologer may call that a stellium. It names a pattern of positions, not a verdict about a person.
A group, not another planet
A stellium is a group of planets close together in one area of a chart. The word describes where the planets sit. It is not the name of a separate object in the sky.
The count depends on the source
Some modern guides use the term for three or more planets in one sign or house. Older descriptions expected four or five packed closely together. If an app calls a group a stellium, check which planets it counted and how close they are.
Look at the planets before the label
A group gives you a place to start reading: which planets are there, and what does each one symbolize? The label alone cannot tell you someone's personality or predict an event.
A few common questions
Do three planets always make a stellium?
No. Some modern sources count three in one sign or house; others require more planets and a tighter group. Check the rule your source uses.
Sources & further reading
Astrology sources describe their own traditions and methods; they do not establish predictive accuracy. The writing exercises are original Lodestar editorial material.