noun Download 🔗Share A reflective optical prism containing a section where two faces meet at a 90° angle, resembling the roof of a building. Reflection from the two 90° faces returns an image that is flipped laterally across the axis where the faces meet. Examples : "The binoculars used for birdwatching contain roof prisms to correct the image and make it appear right-side up. " technology physics device Chat with AIVocabulary GamePractice Reading