ptilosis

1. (ornithology) The appearance or study of feathers on a bird, including factors such as their texture or shape.Examples: "Pterylography must be based on the distribution of the follicles, for the ptilosis as seen externally does not reflect the actual pterylosis."uncountableusually

2. (medicine) Loss of the eyelashes, due to ulceration or other damage to the follicles.Examples: "The state of the lid, when deprived of the eyelashes, has been called ptilosis or alopecia ; the effect of the removal is very inconsiderable, and unless you look closely to the lid of a person of light hair, you can hardly distinguish whether the eyelashes are wanting or not."; "This is an aggravated form of the last disease, and presents ulceration and induration of the edges of the eye: lids, so as to cause the cilia, or lashes to fall out—ptilosis."; "Loss of the eye-lashes, (ptilosis, madarosis, alopecia.) -- Destruction of the bulbs by ulceration or by injury causes permanent loss of the cilia, which may be either total or partial."uncountableusually