Facial symmetry is a term that we use to describe how much the left and right sides of a person’s face mirror each other. Essentially, it’s a measure of how alike the two halves of a person’s face are when it comes to the size, shape, and positioning of their facial features. When a face is symmetrical, it means that if you were to draw a line down the middle of the face, the two halves would be very similar or nearly identical to each other.