See:
Red Valentino Pleated wool dress
Dress from Red Valentino. This bon ton item, with half sleeves and knee lenght skirt, is two coloured knitted made. It softly enhances the silhouette and .
www.lindestore.com/eng/product/2138/ - Cached - Similar

--------------------------------------------------
Note added at 34 mins (2009-08-12 09:06:46 GMT)
--------------------------------------------------

We can try crimped wool as well.
See:
The effect of worsted and semi-worsted processing on artificially ...
The effect of worsted and semi-worsted processing on artificially crimped wool. an investigation into the permanence of artifical crimp on wool as affected ...
openlibrary.org/b/OL13694015M - Cached - Similar

Not sure - this is just a bit of detective work.

crinkle wool A wavy or crinkled effect that is produced by treatment with sodium hydroxide (caustic soda) under highly controlled conditions.

crinkle silk (also known as plissé: pronounced plee-say) A silk that is given a crinkled or pleated effect through chemical application or mechanical means.
http://www.jjill.com/jjillonline/artandcraft/glossary.aspx?A...

Crinkle Cotton
Cotton that is treated to give it a rich, plissé texture in the warp that requires no ironing.
Plissé
Fabric with a puckered surface. French word meaning gathering, folding, pleating.
Pucker Knit
A plissé fabric with a crinkled or puckered effect; usually some spandex is required to create this textured, stretchy surface.
http://designsbydorice.com/glossary.aspx

http://books.google.co.uk/books?id=vCOV2x4d7hkC&pg=PA166&lpg... (page 166)

just a guess

"Folded yarn is produced by twisting two or more singles yarns together; many fabrics use plied yarns.

In the recent years, researchers and industrial companies worldwide have been showing an increasing interest in rigidity textile products."

Sometimes things are exactly what the name says: folded yarn. :-) Another way of saying it is plied yarn.

References:
Folded Yarn
http://www.diba-fiberglass.com/folded_yarn.htm

Folded Yarn. - Yarn is folded to impart increased strength, elasticity and smoothness, and is used, both glazed and unglazed, for warp and weft in ordinary fabrics. It is also made for such special purposes as sewing, lace-making, crocheting and hosiery. The counts of these yarns are expressed according to the number of threads twisted together, as 2/50 s, 3/60 s; the former indicating that two threads of 50 s, and the latter three threads of 60 s, were twisted together to yield yarn of 25 hanks and 20 hanks per lb respectively; the count of the single yarn being invariably named in the cotton, linen, woollen and worsted trades. With spun silk the practice adopted is to name the count of the folded yarn; thus, 70/2 and 40/3 imply that two threads of 140 s and three threads of 120 3 were respectively folded together. Sewing Cotton should be smooth and strong, and much of it is from two to six cord. When two or three cord, the doubling twist is in the opposite direction to that of the singles. When more than three cord, it usually undergoes two twistings, the first in the same direction as the single threads, the second is in the opposite direction to, and more closely twisted than the first. Thus: - A six-cord thread is first folded and twisted two into one, then three strands of two fold are twisted into one; after which it is sized and polished. Lace Yarn should be strong, elastic, smooth and spun twist way in the singles, but doubled weft way. Crochet Yarn is bulky, elastic and has a corded appearance. It is twice doubled: the first time it is twisted in the opposite direction to the singles, the second time in the same direction as the singles. HosieryYarn is often a soft, bulky, single thread, but it is also folded, sometimes without being twisted, at other times it is slightly twisted. There are two types, namely, wool and silk, neither of which need be made from the fibres named. For the former a hairy surface is not objectionable, but the latter should be smooth, and may be gassed. Polished Yarn may be either single or folded, but it should be fully twisted and level. It is bleached or dyed in hanks, immersed in size and polished with brushes while the size is moist.
http://www.1911encyclopedia.org/Yarn

Yarn is single, folded and See also:
• FANCY (a shortened form, dating from the 15th century, of " fantasy," which is derived through the O. Fr. fantasie, modern fantaisie. from the Latinized form of the Gr. cbavraoia, Oavrai'ecv, Oat Pais, to show)
fancy, and if See also:
• TWISTED
twisted to the right it is called twist way, and if to the See also:
• LEFT
left, weft way, but those terms do not necessarily imply that the yarn is for either warp or weft .
http://encyclopedia.jrank.org/YAK_ZYM/YARN.html

Folded Yarn: Plied yarn
http://www.bellaonline.com/articles/art12300.asp

Yarn Configurations: Single Versus Plied
Once a group of single filaments or a group of staple fibers is twisted or spun into a yarn, it can be referred to as a single yarn.
Most basic yarns are either single or plied (the HTSUS calls plied yarns “multiple” or “folded”). A single filament yarn could be a single multifilament yarn, which is one collection of parallel filaments grouped together, or twisted together in the same direction, or a single filament (a monofilament) intended for use in the production of a fabric. A single staple fiber yarn would be a yarn that has been made by spinning (winding) a collection of staple fibers all in the same direction.
Two or more single yarns can be twisted with each other to form a plied or multiple or folded yarn. Generally, the direction of the twist in such a yarn would be the opposite of the direction of the twist of the single yarns that make up the plied yarn. Two or more plied yarns, when twisted together, in turn become a cabled yarn.
www.nationaltextile.org/library/customs/icp005r2.pdf



--------------------------------------------------
Note added at 20 hrs (2009-08-13 04:38:25 GMT)
--------------------------------------------------

Correction: plied wool yarn

Oops! I forgot to put wool in the translation box! Also, I couldn't find an example of "folded wool yarn" even though plied yarn is a synonym for folded yarn.

• Yarndex Knitting + Crochet Directory - Search Results
Browse All Yarns with Fiber Content "Linen" ... by Louet North America -- a washable and dryable fingering weight plied wool yarn ...
www.yarndex.com/search.cfm?action=search_basic&ss=Linen Pli... - 235k - Cached

• CORIN TUCKER handspun hand dyed plied wool yarn by ladylazarusplath on Etsy
CORIN TUCKER is the 5th installment of my inspiring women series of yarns. ... CORIN TUCKER handspun hand dyed plied wool yarn. Description ...
www.etsy.com/view_listing.php?listing_id=19855547&ref=cat3_... - Cached

• Knitting Information, Tips, and How-Tos
Knitter's Review is a free weekly online knitting magazine dedicated to yarn, ... a spindle, take a piece of plied wool yarn about 18 inches long and tie it ...
www.knittersreview.com/goto.asp?goto=howtospin - Cached

Oops! I forgot to included