Q From Margaret Sonmez: I wondered about the origins of the following term which I have never come across outside knitting patterns:
A Purl is from an obsolete Scots word pirl, which means a “twist”. It was applied in the sixteenth century to a thread or cord made of twisted gold or silver wire that was used for embroidery. It may be that it was then transferred by analogy to the ribbed look of purl knitting, though the OED has a note saying that the derivation is far from obvious. It is sometimes spelled pearl, which may be a mistake, but may equally imply a different origin.