i Register
In some senses, shoulder-knot is marked as historical. Watch for register when choosing this word.
noun
An ornamental knot of ribbon or lace worn on the shoulders of fashionable men's jackets, especially in the 17th and 18th centuries.
‘May I?’ she whispered, smiling round into his face. His shoulder-knots just perceptibly rose.
A similar ornament of other materials worn on a military dress uniform.
A moth bearing a resemblance to such ornaments.