Short answers, pulled from the story.
The word yarn emerged from Middle English, carrying a meaning that once referred to human entrails. This linguistic journey traces back through Old High German and Dutch before settling into its modern textile definition.
Human production of yarn dates back to the Stone Age when people first twisted animal hides and reeds together. Upper Paleolithic communities developed spinning techniques that would eventually evolve into complex machinery.
Silk production began in China and was well-established by the Shang dynasty between 1600 and 1050 BCE. Bombyx mori moth larvae produce the protein fiber fibroin that forms silk threads.
Denier and Dtex measure weight per linear measurement for these materials. Synthetic fibers appear in three basic forms: staple cut lengths up to 120 mm, tow ropes with many filaments loosely joined side-to-side, and filament strands ranging from one to many continuous elements.
Twisting direction determines whether the yarn has s-twist going up to the left or z-twist going right. Galileo first studied the mechanical integrity derived from frictional contacts between composing fibers.
The Craft Yarn Council of America promotes standardized industry systems numbering weights from 0 to 7. Size 0 represents Lace weight while size 7 indicates Jumbo thickness.