words not plural ending in s

The most widely held view is that denim is an English corruption of the French term "serge de Nimes;" meaning a serge fabric from the town of Nimes in France. The term serge means a twill-weave fabric with a characteristic diagonal wale… Serge de Nimes was very different than denim. It was made of silk and wool, but denim has always been made exclusively of cotton.

...To confuse the issue even more, at this same time, another fabric known as "jean" is known to exist. Research on this textile indicates that it was a fustian (a cotton, linen and/or wool blend) and that the fustian of Genoa, Italy was called jean....

Jean fabric was apparently quite popular, and the English imported it in large quantities as early as the 16th century. By the 18th century, jean cloth was being made completely of cotton, and used to make men's clothing, valued especially for its durability even after repeated washings.

Denim's popularity was also on the rise. It was stronger and more expensive than jean, and though the two fabrics were very similar in other ways, they did have one major difference: denim was made of one colored thread and one white thread; jean was woven of two threads of the same color.

While denim and jean apparently originated in France and Italy, it is likely that they were transmitted to America via England.... English mills may have used the continental names and substantially changed the fabric and manufacturing process.

What a wealth of information this thread is! Here's my contribution: Growing up, we referred to "dungarees" what are known elsewhere as "jeans." The American Heritage College Dictionary says this word derives from the Hindi dumgri, but it doesn't define that word. Oh, to have a better reference tool at my disposal!

denim: durable twill-woven fabric with coloured (usually blue) warp and white filling threads; it is also woven in coloured stripes. The name is said to have originated in the French serge de Nîmes. Denim is yarn-dyed and mill-finished and is usually all-cotton, although considerable quantities are of a cotton-synthetic fibre mixture. Decades of use in the clothing industry, especially in the manufacture of overalls and trousers worn for heavy labour, have demonstrated denim's durability. This quality also made denim serviceable for leisure wear in the late 20th century. See also jeans.

jeans: also called Blue Jeans, Dungarees, Denims, or Levi's, trousers originally designed in the United States by Levi Strauss in the mid-19th century as durable work clothes, with the seams and other points of stress reinforced with small copper rivets. They were eventually adopted by workingmen throughout the United States and then worldwide.

Jeans are particularly identified as a standard item of "Western" apparel worn by the American cowboy. After the mid-20th century, various adaptations became internationally a characteristic part of clothing for both men and women. See also denim; Levi Strauss & Co.