Mode is the way something behaves.
Pixel is a contraction of the words picture and element.
The 40-column and 80-column formats are two text modes. A third way that applications can send information to your monitor is in graphics mode. In graphics mode, text and graphics are formed by patterns of dots, or pixels. The more dots used to create a picture the sharper the resolution. The Apple IIGS can display graphics by using a rectangular array of 640 horizontal by 200 vertical dots. In this mode, called super-high resolution, the dots are so close together that it's hard to tell that the picture is made up of dots. The Apple IIGS also supports graphics modes developed for earlier models of the Apple II, including double-high resolution, high resolution and low resolution.
The phrase graphics mode suggests that this way of sending information to the screen applies only to pictures, but graphics mode can also be used to display text. In fact, that's how some word processing applications are able to display text in a variety of sizes and fonts. Instead of using the Apple IIGS's built in text generator (which fits characters into the 40-by-24 or 80-by-24 grid), they send numbers and letters to the display as if they were pictures.
Most of the time, you'll be using the computer to create something: a letter, a graph, a list, a budget. Things you create with the computer are called documents, or files. The kind of document you can created depends on the application you're using. You don't create a letter by using a spreadsheet application, and you don't create a spreadsheet by using a word processing application.
As you type your document, it is stored along with the application in the memory of the computer.
