I. quad ‧ ru ‧ ple 1 /ˈkwɒdrʊp ə l, kwɒˈdruː- $ kwɑːˈdruː-/ BrE AmE verb [intransitive and transitive]
to increase and become four times as big or as high, or to make something increase in this way ⇨ double , triple :
Food prices quadrupled during the war.
The company has quadrupled its profits in just three years.
II. quadruple 2 BrE AmE adjective , predeterminer
1 . four times as big or as many ⇨ double , triple :
The subjects were given quadruple the normal dosage of the drug.
2 . involving four things of the same kind:
a quadruple murder