A hologram is a special kind of picture made with laser light, not with an ordinary camera. When you move your head or tilt the picture, it does not stay flat: it looks as if it has depth, as if the thing is sitting in space. You have probably seen tiny holograms on credit cards and tickets — a shiny patch that changes as you move it. Scientists also make larger ones that look a bit like a window with a solid object behind the glass. People stretch the word a lot. Any floating “3D ghost” on a stage or in a phone ad may get called a hologram. Though actually, many of those are just clever lights or screens, not true holograms. Dennis Gabor coined the word in 1948, from Greek pieces meaning “whole” and “something written or drawn.” He later won a Nobel Prize for this work.