A concept is our internal knowledge about the world, and my be rudimentary or very complex.
As a child, I could look up at night and see a twinkling point of light. That’s all it was to me, and I recognized it when I saw it again, and we call it a star.
Concepts, however, typically accrue information and become quite complex. Hence, the twinkling point of light I see and call a star today, I now understand to be a monstrous roiling mass of compressed gas (mostly Helium) being fused by its own weight with a tremendous release of energy.
A star may be many times larger than our sun, depending upon which point of light we are looking at, but has a life cycle that is shorter than our sun.
It will eventually self destruct spewing out atoms heavier than helium and will shrink into a dense lifeless sphere or maybe a point so dense that nothing can escape its gravity--almost.
For the child, there are more concrete concepts to deal with as they strive to become familiar with their environment.