Definition of ptilosis in English:

ptilosis

Pronunciation /tɪˈləʊsɪs/

noun

rare Ornithology
  • The appearance or characteristics of the feathers (especially the down feathers) of a bird; the plumage; the study of this.

Origin

Mid 19th century; earliest use found in Robert Mayne (1808–1868). From scientific Latin ptilosis from Hellenistic Greek πτίλωσις plumage from πτιλοῦν to furnish with wings or feathers (from ancient Greek πτίλον soft feather, down: see ptilo-) + -ωσις.