Raking is not a kind of muting, but a technique for applying it. It is vaguely related to sweep picking, but instead of an arpeggio, the result is usually a single percussive-sounding note. (However, sweep picking is sometimes incorrectly notated as a rake in tablature, and sloppy sweep picking may accidentally become a rake.) Between two and four strings are struck, only one containing the desired note and the rest muted. Rakes may be notated in various ways; the most common way is to add muted grace notes, possibly adding the word "rake" to the tablature for clarification. (Courtesy of Wikibooks)
