In trying to think up a joke about bluejeans, I looked up "jeans" in my dictionary and got a rurpise:
ean 7jcn8
n.
5< ME Gene (fustian), (fustian) of Genoa < OFr Janne < ML Janua < L Genua, Genoa6
1 a durable cotton cloth in a twill weave, used for work clothes and

Which reminds me. In early days of TV, there was a children's program Captain Kangaroo,
with character Mr. Green Jeans.