The Collaborative International Dictionary of English v.0.48:

Fourfold \Four"fold`\, n.
   Four times as many or as much.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fourfold \Four"fold`\, v. t.
   To make four times as much or as many, as an assessment; to
   quadruple.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fourfold \Four"fold`\, a. & adv. [AS. fe['o]werfeold.]
   Four times; quadruple; as, a fourfold division.
   [1913 Webster]

         He shall restore the lamb fourfold.      --2 Sam. xii.
                                                  6.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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