In simple terms, 4K is a term used to signify resolution, or clarity of an image. 4K stands for 4,000, which roughly denotes the number of pixels horizontally.
Just to add to the confusion, there are two broad classes of 4K:

• For Cinema: 4096 horizontal pixels
• For television: 3840 horizontal pixels

Why on earth would we need two standards? It’s a long story, but suffice to say that movies were scanned to 2K (2048 pixels) before 4K, so the number they chose was twice that, which is 4096.
Television, on the other hand, has no 2K, and probably never will. Instead, it has 1920×1080, what we call High-definition, or HDTV. Twice 1920 is 3840.
To avoid further confusion, we’ll stick to these terms:

• 4K Cinema: To mean 4K cinema 4096
• Ultra HD: To mean 4K television 3840
• 4K: to mean both, they’re not too far off you know – 99% of the world won’t be able to tell the difference. The rest are hawks.

The idea is to bring the best possible clarity to your home. See the image above? 4K is marketed to the masses as having so much resolution that it feels like you’re looking out the window into another world.