quadruple

1. (transitive) To multiply by four.Examples: "Quadrupling four gives sixteen."transitive

2. (intransitive) To increase by a factor of four.Examples: "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."intransitive

3. (rail transport) To provide four parallel running lines on a given stretch of railway.Examples: "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."; "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."; "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."