In publishing and graphic design, lorem ipsum is a placeholder text (filler text) commonly used to demonstrate the graphic elements of a document or visual presentation, such as font, typography, and layout, by removing the distraction of meaningful content. The lorem ipsum text is typically a mangled section of De finibus bonorum et malorum (Wikipedia page [1]), a 1st century Latin text by Cicero, with words altered, added, and removed that make it nonsensical and not proper Latin.

More information on the Wikipedia page [2]; there are many relevant websites.

See also Etaoin shrdlu and The quick brown fox jumps over the lazy dog