For each person on this planet the definition of beauty is different. Some may define it on the basis of the looks of a person, for some it is how a person is from within and for some both the inside and the outside complete the definition of beauty. But i would rather say that beauty is completely the perception of different human beings, it is something that pleases our hearts and for every other person the definition of beauty changes. As they say, " beauty lies in the eyes of the beholder."
You aren't what they think you are, you are how you think of others. How you look at people doesn't really define them, but rather the depth of your own mind. This is why it is said that we must never think bad of anyone, because you can't really know all about any person, the only person you have full knowledge of is yourself. You are in no place to judge anyone else for anything because you only look at what you want to see in a person. It is only your perception of who they are and in no way does it define who they really are. Everyone on this planet is different and we all have something unique about ourselves that no one else has. And everyone looks at another person with a different angle, two persons might not see the same in another person. Our minds think in a different way and thus our image of any person is different from others. The features in a person that pleases our hearts and satisfies our minds, we call them beautiful.
And in no way do the looks of a person defines his/ her beauty. It is something that a person is born with, it is how God chose to make us. If any person comments on how a person looks, they only make a judgement on how God creates. If you really have to say something about a person, look at their hearts, look how they think. But no person can know the condition of another's heart. No one knows what's hidden behind one's actions, why they do what they do. We might perceive things according to us, but that doesn't really mean that we are right about them. It might not be how we think it is.
We all are creatures of the same God and no human was made superior to another in any aspect. If a person lacks in something, he would definitely have something that is better than that of what others have. We all have been gifted with different mindsets, and how a person thinks defines his personality.
We must never take the opinions of others about us personally. Everyone has something to say about us, but what we feel about ourselves matters the most.
We are all differently beautiful.