A Catseye is one of a line of small, hard studs fixed in the road, often down the middle. At night, car lights hit them and they shine back, so a driver can still see the lane when it is dark or wet. The picture is a cat’s eye in a torch beam: it throws light straight back. The name began as a British brand; you will also see cat’s eye and cats-eye. In American English people more often say reflector or raised pavement marker. Though actually cat’s-eye is also the name of a gemstone with a sliding line of light across it — that is a different thing. This word, in this sense, is the road stud. They were first made in Britain in the 1930s; the inventor was Percy Shaw.