Microsoft Word - Microsoft Word is a commercial word document processor for Windows.
Apache OpenOffice - Apache OpenOffice is an open source, office document productivity suite.
LibreOffice - Writer - Open-source cross-platform word processor.
Caret - Better Markdown Editor for Mac / Windows / Linux
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Scribes - A text editor for GNOME that combines simplicity with power.