Answer :HD means high dimensional.3D means three dimensional. Normal means not having these two features.
Answer :HD - High definition 3D - 3 dimensional normal Tv - standard definition. HD Television - High definition television that has resolution substantially higher than normal televisions. HD TV has one or two million pixels per frame roughly five times the standard definition (normal tvs). A 3D television (3D-TV) is a television set that employs techniques of 3D presentation, such as stereoscopic capture, multi-view capture, or 2D-plus-depth, and a 3D display – a special viewing device to project a television program into a realistic three-dimensional field.