Pronounced as wiz-zee-wig. WYSIWYG is short for what you see is what you get. It is a term coined by Charles Simonyi in 1974 to describe an application able to display a file or document exactly as it will appear when printed or viewed. A good example is a WYSIWYG HTML editor, which allows you to edit a web page with little or no HTML knowledge.
Tip: This term is WYSIWYG, not WYS1WYG, which is a common misspelling of WYSIWYG; the I (i) is not a 1 (one).