pterylosis

noun

pter·​y·​lo·​sis

ˌterəˈlōsə̇s

plural pteryloses

-ōˌsēz

: the arrangement of feathers in definite areas of growth

birds … at least three years old judging from the pterylosis of the head

—American Midland Naturalist

Word History

Etymology

New Latin, from pteryla + -osis

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