A Stellium is when there are a number of planets in the same sign or house. It indicates an unusually strong focus on the sign or house where it is located.
A Stellium is a group of planets that are in the same sign or house. It indicates an unusually strong focus on the sign or house where it is located.
The planets may or may not also be conjunct or aspected to each other (which would be a Multiple Conjunction or Rolling Conjunction).