The question is what general characteristics are possessed by all beautiful objects, or all objects that have aesthetic value. Definitions can be too broad . Suppose we define 'bachelor' as 'unmarried male'. On first glance this might look all right, but it applies to a lot of things, for example, male dogs, and male babies, that, needless to say, are not bachelors. A definition is too broad if it applies to things that are not part of the extension of the word defined.
Definitions can be too narrow .
So even though some pieces of furniture are objects that are used to sit on, not all furniture is used to sit on. We might also choose to entirely rewrite the definition, since laundry lists of characteristics strung together by 'or' are generally regarded by philosophers as not describing a unitary concept. Definitions can go wrong by using ambiguous, obscure, or figurative language. Suppose we defined 'love' as 'the insensible quivering of the soul'. This is useless.