What is a peck of peppers?

A peck of peppers is equivalent to two gallons or eight dry quarts of peppers. The term "peck of peppers" is commonly familiar from the Mother Goose nursery rhyme "Peter Piper."

A peck is a U.S. Customary and British Imperial Systems unit of measurement for volume. It was initially used to measure flour. In Great Britain, four pecks are equivalent to one bushel. A common version of the nursery rhyme from which the term "peck of peppers" was coined is as follows: "Peter Piper picked a peck of pickled peppers./ A peck of peppers Peter Piper picked./ If Peter Piper picked a peck of peppers,/ Where's the peck of peppers that Peter Piper picked?"