Etymology From Middle English quadruple, from Latin quadruplus. Can be analyzed as quadri- + -ple.
1
To multiply by four.
Quadrupling four gives sixteen.
2
To increase by a factor of four.
Our profits quadrupled when we made the improvements.
Overall, consumer spending on fast tech has quadrupled to £11.6bn since 2023, surveys carried out for Material Focus suggested.2025 June 25, Chris Vallance, “'Fast tech' warning as demand for cheap gadgets heats up”, in BBC, archived from the original on 26 Jun 2025:
On June 8, 1872, the London & North Western Railway obtained powers to quadruple its main line, and a new tunnel was bored for the up and down slow lines.1950 September, “Network News: Watford Tunnel, L.M.R.”, in Railway Magazine, page 641:
Quadrupling the short remaining stretch of three-track railway north of Rugby, left over by the turn of the century modernisation, is a possibility that could be pursued.2019 October 23, “Railtalk: HS2 delay - time for lateral thinking”, in Modern Railways, page 7:
1 more example
A long-term aspiration is to quadruple the cross-country route between Peterborough and Werrington Junction, removing any conflict between trains on the Spalding and Leicester lines.2020 April 22, Paul Shannon, “Felixstowe: Is 47 trains a day achievable?”, in Rail, page 52: