How to explain light

Last week I was driving with my mother in L.A. and the typical conversation about school came up. I started explaining to her about the lighting class and how light affects the atmosphere of a play and she asked me, "What is light"? This has to be the simplest question out there but I didn't know what to answer her, I didn't have an explanation for what light is and I gave her the usual, "Light is energy" answer. She wasn't satisfied by that answer so I started telling her that light is energy and also a measure of speed and that sun light gets to us in 8 minutes. Basically I started b.s.ing my way across so that I didn't sound like an idiot, and when I dropped her home I started thinking deeply on what light is and I started reminiscing on my childhood and I used to thing that light was electricity, and even now at the age of twenty I still don't know what light exactly is. In high school I used to be really good in physics but I never thought of the question of light and its relevance to electricity. In the end I resort back to the "light is energy" answer, since I can't think of a more detailed explanation.