What is "phototherapy"

Phototherapy \Pho`to*ther"a*py\, n. (Med.) The application of light for therapeutic purposes, esp. for treating diseases of the skin. -- Pho`to*the*rap"ic, Pho`to*ther`a*peu"tic, a.

n. The use of light to treat disorders of the skin, and certain mood disorders.

n. the use of strong light to treat acne or hyperbilirubinemia of the newborn