This is the Światło wyłączone icon for Windows 10. Here we go. Optimized for 32x32 px, these are the simplest icons in the line style. Downloadable formats are PNG and SVG, among others. Icons8 icon pack is unique in providing a huge number of icons designed by the same team of four designers who create the new icons every working day in the same style and with the same quality. Same cool as the Bat Face, huh.
This is a lightbulb indication to show that the light is turned off. It shows a lightbulb, with a large bulbous circle at the top which tapers off onto the bottom, and there's a large X in the middle to indicate the light is off.