Okay kiddo, have you heard of high-definition TV? Well, 1440p is a type of high-definition TV. It's like having a really clear picture on your TV.
The number 1440 actually tells us how many pixels (tiny dots of color) there are on the screen. More pixels means a clearer picture.
Some people might call 1440p "2K" because it's roughly twice as many pixels as the old standard of 720p. But don't worry too much about that. Just know that 1440p is a really cool way to watch movies and TV shows with great picture quality.