You are the light of my life is a commonly used online phrase that usually appears in novels, anime, games, and other fictional works. It literally means you are the light of my life. The meaning of this word depends largely on the context, but it is usually used to express the value and significance of the protagonist to another person or the special care and love he or she has for someone. In this context, you are the light of my life means that the protagonist thinks that the other person is the most important person in his life. He wants the other person to live well and is willing to give everything for the other person. It should be noted that the context and interpretation of this word may vary from work to work, so the specific meaning needs to be understood according to the specific context.