what is aggregation in oop?

In Object-Oriented Programming (OOP), aggregation is when an object contains a reference to another object, or to a collection of other objects. This means that one object can "point" to another, allowing for objects to be grouped and organized together. For example, a classroom might be made up of a teacher, a bunch of students, and the desks they sit at. The teacher and the students could be one type of object and the desks another, and the classroom object could "point" to both of these objects to keep track of them.