quadruple, quadruplicate, quadruplex, fourfold, four-fold -- (having four units or components; "quadruple rhythm has four beats per measure"; "quadruplex wire")
quadruple, fourfold, four-fold -- (four times as great or many; "a fourfold increase in the dosage")
Overview of adv four-fold
The adv fourfold has 1 sense
fourfold, four times -- (by a factor of four; "the price of gasoline has increased fourfold over the past two years")