Where does the term “Rasher” come from and What does Rasher mean?

In the United States, we refer to “a slice of bacon”; our British cousins more commonly would order “a rasher of bacon,” and expect to receive the same portion implied by our term, a single thin slice.

Some have suggested that the rasher is so-called because, being thin, it may be cooked rashly (“quickly”).

Others prefer to believe that the word is derived from the long-obsolete verb, to rash, “to cut, slash.

We find more plausible than either the suggestion made by Dr. James Mitchell in his book, Significant Etymology, where he offers the theory that rasher is a misspelling of rasure, “a thin slice, a shaving,” from the Latin verb rado, rasi, rasum, radere, “to scrape, shave, scratch.”