fourfold UK /ˈfɔːfəʊld/US /ˈfɔɹ.foʊld/adjective 2adverb 1noun 1verb 1forms 3 adjective2 •Four times as great; quadruple. •Comprised of four individual members.Most pupils have a fourfold object in studying a language; they wish to be able to read and write, to speak and to understand it. — 1895 adverb1 •By a factor of four.And he shall restore the Lambe fourefold, because he did this thing, and because he had no pittie. — 1611 noun1 •An algebraic variety of degree 4.Our main application is to the classification of Poisson brackets on Fano fourfolds. — 2015 verb1 •To increase to four times as much; to multiply by four. formsfourfolded · fourfolding · fourfolds