a set of four similar things considered as a unit
a quantity that is four times as great as another
To multiply by four.
having four units or components
"quadruple rhythm has four beats per measure"
"quadruplex wire"
Being four times as long, as big or as many of something.
The word comes from the Latin quadruplus, which literally means "fourfold." It is formed by combining the prefix for four with a suffix meaning times or fold.