definition of
fourfold

[1] #1 fourfold s. [quadruple, four-fold] four times as great or many; "a fourfold increase in the dosage". wn

[2] #2 fourfold r. [four times] by a factor of four; "the price of gasoline has increased fourfold over the past two years". wn

[3] #3 fourfold s. [quadruple, quadruplicate, quadruplex, four-fold] having four units or components; "quadruple rhythm has four beats per measure"; "quadruplex wire". wn