Readable means easy to understand or comprehend. It refers to something that is clear and coherent, making it not difficult for someone to read or comprehend the information presented. Full definition
There is no glare, and the screen is even more readable in sunlight than it is indoors; the brighter the ambient light, the better the display looks. (tabletpcreview.com)
A PDF is designed to look like the actual book in print, while an ebook is designed into a more readable format on eReader. (alphaebook.com)
The goal is to make the words as easily readable as possible. (hubpages.com)