Source : Webster's Revised Unabridged Dictionary (1913)

Fourfold \Four"fold`\, a. & adv. [AS. fe['o]werfeold.]
   Four times; quadruple; as, a fourfold division.

         He shall restore the lamb fourfold.      --2 Sam. xii.
                                                  6.

Fourfold \Four"fold`\, n.
   Four times as many or as much.

Fourfold \Four"fold`\, v. t.
   To make four times as much or as many, as an assessment,; to
   quadruple.

Source : WordNet®

fourfold
     adj 1: four times as great or many; "a fourfold increase in the
            dosage" [syn: {quadruple}]
     2: having four units or components; "quadruple rhythm has four
        beats per measure"; "quadruplex wire" [syn: {quadruple}, {quadruplicate},
         {quadruplex}]

fourfold
     adv : by a factor of four; "the price of gasoline has increased
           fourfold over the past two years" [syn: {four times}]