Definition from Wiktionary, the free dictionary
stiffener (plural stiffeners)
- Anything added to something in order to stiffen it, such as a support beam, or starch for a collar.
- 1856: Charles Dickens, Sketches by Boz: Illustrative of Every-day Life & Every-day People 
- ... he wears a wisp of black silk round his neck, without any stiffener, as an apology for a neckerchief...
- 1901: James Nisbit Hazlehurst, Towers and Tanks for Water-works: The Theory and Practice of Their Design and Construction 
- ...each of these stiffener-columns must be designed to resist approximately 26 tons. Sometimes single angles are thus used as stiffeners...
- 1904: Edward L. Attwood, War-ships: A Text-book on the Construction, Protection, Stability, Turning, Etc., of War Vessels 
- The tee bar (b) is used as a stiffener to important bulkheads...
- 1856: Charles Dickens, Sketches by Boz: Illustrative of Every-day Life & Every-day People