A 3-D film or picture is made so it seems to have length, width, and depth — so people and things look less flat, more “in the room”. 3-D is short for three-dimensional. You also hear it with glasses in a cinema, and with 3-D printing, which builds a real solid object layer by layer. People often write 3D with no hyphen. Though actually, a lot of 3-D on a phone or TV is still a trick for the eyes; you are not holding a solid thing unless someone has printed or carved it. 2-D is the flat version of the same idea.

3D、立體。台灣都講「3D電影」「3D列印」，較少說「三維」。