fourfold

adjective

1. four times as great or many

- a fourfold increase in the dosage

Similar word(s): multiple, quadruple

2. having four units or components

- quadruple rhythm has four beats per measure

Similar word(s): multiple, quadruple, quadruplex, quadruplicate

adverb

1. by a factor of four

- the price of gasoline has increased fourfold over the past two years

noun

1. (mathematics) An algebraic variety of degree 4.

verb

1. to increase to four times as much; to multiply by four