A word processor is an application which a type of text editor, used in document preparation systems, for creating documents for publication. Using a bit-mapped display, they usually show the document exactly as it would appear when printed (with multiple fonts, bold and italic, etc); the so-called WYSIWYG interaction paradigm. They stored their files in private formats (often including binary data), not intended for direct use by users. They always included an editing function, and can usually edit ordinary text files, as well as their private enhanced formats.
The first word processor was Bravo, created at Xerox PARC for the Alto. In some ways, it was an intermediate between older screen editors, and what we now recognize as a word processor; it had the ability to display the 'ready to print' form, but also had a more usual text editing display.