quadruples

Verb

quadruple (third-person singular simple present quadruples, present participle quadrupling, simple past and past participle quadrupled)

1. (transitive) To multiply by four.
   • Quadrupling four gives sixteen.
2. (intransitive) To increase by a factor of four.
   • Our profits quadrupled when we made the improvements.
3. To provide four parallel running lines on a given stretch of railway.
   • 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

See all 6 meanings of quadruple