stiffener

plural stiffeners

1. Anything added to something in order to stiffen it, such as a support beam, or starch for a collar.

   The tee bar (b) is used as a stiffener to important bulkheads […]

   1904, Edward L. Attwood, War-ships: A Text-book on the Construction, Protection, Stability, Turning, Etc., of War Vessels

   3 more examples

   […] he wears a wisp of black silk round his neck, without any stiffener, as an apology for a neckerchief […]

   1856, Charles Dickens, Sketches by Boz: Illustrative of Every-day Life & Every-day People

   […] each of these stiffener-columns must be designed to resist approximately 26 tons. Sometimes single angles are thus used as stiffeners […]

   1901, James Nisbit Hazlehurst, Towers and Tanks for Water-works: The Theory and Practice of Their Design and Construction

   […] with this arrangement the cylinders are cast separately from the saddle, and bolted to the frames on each side with a fabricated stiffener between the frames. This stiffener is carried up to form the saddle for the smokebox, and within it is fitted the exhaust pipes from the cylinders to the blast pipe.

   1944 November and December, “Modified G.W.R. "Hall" Class Locomotives”, in Railway Magazine, page 350

2. businessOne of a series of angle bars, Z-bars, beams, rods, or other shapes, attached in order to provide them the necessary stiffness or rigidity.
3. slangAn alcoholic drink taken to fortify oneself.

   I believe the old man has taken himself off to the nearest bar for a stiffener.

   2017, William Meikle, Sigils and Totems