What is Aesthetics?

Legal Definition
Aesthetics (/ɛsˈθɛtɪks/; also spelled æsthetics and esthetics also known in Greek as Αισθητική, or "Aisthētiké") is a branch of philosophy dealing with the nature of art, beauty, and taste, with the creation and appreciation of beauty. It is more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgements of sentiment and taste. More broadly, scholars in the field define aesthetics as "critical reflection on art, culture and nature". In modern English, the term aesthetic can also refer to a set of principles underlying the works of a particular art movement or theory: one speaks, for example, of the Cubist aesthetic.
-- Wikipedia
Legal Definition
A beautiful image or element. It usually has darwinistic symmetry.