Definition of plica polonica in US English:

plica polonica

noun

Medicine
historical
  • A matted condition of the hair, generally associated with poor hygiene and pediculosis.

Origin

Mid 17th century; earliest use found in Alexander Ross (1591–1654), Church of England clergyman and writer on philosophy. From post-classical Latin Plica Polonica from plica + Polonica, feminine singular of Polonicus Polish.