rogue's yarn

English

Noun

rogue's yarn (plural rogue's yarns)

1. (naval, historical, slang) A thread of red, blue or gold worsted, worked into the ropes manufactured in the government Royal dockyards, to identify them if stolen. Red for Pompey (Portsmouth), Blue for Guz (Plymouth), Gold for Chatham. Also a blue thread worked into canvas for the same purpose.

References

• John Camden Hotten (1873) The Slang Dictionary