Facial symmetry
How closely the left and right halves of a face mirror each other; every face is slightly asymmetric.
Also: symmetry
No face is perfectly symmetric. Small differences between the two sides, in brow height, eye size, nostrils or the jaw, are normal, and a photo made by mirroring one half of a face usually looks odd. Psychology studies have found that people tend to rate more symmetric faces as a little more attractive, though the effect is modest and varies across studies. Symmetry says nothing about a person's character or health in any useful everyday sense.