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Webster 1913 Edition

Noun.

[F.

jaconas

A thin cotton fabric, between cambric and muslin, used for dresses, neckcloths, etc.

[Written also

jacconet

Noun.

A kind of coarse muslin.

jaconet ‎(countable and uncountable, plural jaconets)

A type of cotton cloth, especially as dyed and waterproofed.
- 1979: It really was beautifully executed, more like a forgery than a copy, for the copyist had laid it down on a jaconet backing and had even added a cachet de vente, a couple of collectors' marks and a museum reference numer. — Kyril Bonfiglioli, After You with the Pistol (Penguin 2001, p. 321)