double file

double file (plural double files)

1. A double line, especially, a queue two persons wide.
   • 1864, United States War Department, The 1864 Field Artillery Tactics, Stackpole Books, published 2005, →ISBN, page 120:

     The column marching in double file, the instructor commands: […]

   • 1891, Nettie D. Kimberlin, in Annual Report of the Controller of the City of Detroit of the Receipts and Expenditures of the Corporation, The Smith Printing Co., page 30:

     In marching by double file, four abreast, etc., elbows touch and no lagging should be allowed.

   • 1942, Francis Ernest Lloyd, The Carnivorous Plants, READ BOOKS (publisher, 2007), →ISBN, page 100:

     There are three double files of stalked glands, one along each leaf margin, roughly speaking, and two rows along the under leaf surface, […]

• biofuelled, double life