Imagine you have a toy car and you want to decorate it with stickers. You have a bunch of stickers that are identical and you want to put them on the car in a symmetrical pattern.
Cyclic symmetry in three dimensions is kind of like that, but instead of stickers on a toy car, it's the way an object looks the same after being rotated around a center point. This means that if you look at the object from a certain angle and then spin it around, it will look the same as before.
For example, let's say you have a sphere and you draw a line through the center of the sphere. If you rotate the sphere around that line, it will always look the same. This is an example of a type of cyclic symmetry called axial symmetry.
There are other types of cyclic symmetry too, like rotational symmetry and helical symmetry. These all have to do with the way an object looks the same after being rotated in a certain way.
So essentially, cyclic symmetry in three dimensions is all about how an object can look the same after being rotated around a center point. Think of it like a really fancy way of decorating a toy car with stickers that all look the same!