Google claims that the origin of the word "feather" is related to the origin of the Greek pteron, meaning 'wing' or 'oar', while Etymonline goes no further than the Old English feðer, which is 'a feather or a pen' in the singular and 'wings' in the plural, before then positing the theoretical Indo-European root. The Latin penna, 'feather,' also comes from the same root.
As a verb, "to feather" first meant "to fit with feathers" (as you might do with an arrow) in the early 1200's, and by the late 1400's it could be used to mean "to provide with plumage." By 1782 it is used in the sense of whittling down to a thin edge.
Among the Cheyenne, the first warrior who managed to touch an enemy during battle without being harmed received an eagle feather; in this manner he could continue to collect feathers and thus construct a headdress. Brewer however states that most native Americans collected feathers after slaying an enemy, and that the phrase "A Feather in your Cap", meaning an honor or achievement, derives from that custom. He states that people from Afghanistan, Ethiopia, Turkey, and Hungary all used to do the same thing.
"In high feather" means "full of happiness." Brewer states that "When birds are moulting they mope about, but as soon as they regain their feathers their spirits revive."
Shakespeare uses the word to mean "of the same type or kind," for example, in Timon of Athens : "I am not of that feather to shake off my friend, when he must needs me." The phrase "birds of a feather" uses the word in the same sense.
The phrase "to knock someone down with a feather" means "to astonish." William Cobbett used the term in 1821 in his book Rural Rides. It used to be an old-timey phrase but has had a weird revival since the early 2000's as magazines and newspapers started using the phrase.
One person who suffered a bit more from feathers (or rather the arrows attached to them) was Saint Sebastian, the patron saint of archers. As a Roman soldier he attempted to convert some of his fellows to Christianity, and was punished by coming under a hail of arrows and being left for dead; he didn't actually die from the arrows however, and instead recovered, only to be beaten to death on the orders of Diocletian. Despite this, painters usually depict his martyrdom as the moment of his arrow-skewering, as in The Martyrdom of Saint Sebastian by the Pollaiuolo brothers. He was also the person to which people prayed in the hopes of being spared from the plague - the connection there is to the fact that Homer, in The Iliad, describes the plague as being caused by Apollo the Far-Shooter in terms of that god striking down the population with his arrows (well, first he shoots down the mules and dogs, and THEN he goes for the people; presumably the Greeks should have picked up on this warning).
Moving from renaissance Europeans to the ancient Greeks one naturally arrives at the ancient Egyptians. There, the feather symbolizes justice. When someone dies they would have their heart weighed against a feather belonging to the goddess Maat (which means Justice); if the heart outweighed the feather, the dead person would be unceremoniously - or rather, ceremoniously - fed to Ammut, "the Devourer." The Book of the Dead however provided a spell which, if recited, would prevent the heart from failing the test, which was rather handy.
One way to possibly avoid dying in the modern age, assuming you are flying and have control of the cockpit, is to feather the propeller on a failed engine, which means to increase the pitch of the blade. This will reduce drag allowing you to stay aloft longer.
In contrast, if you are on the ground riding a motorcycle and have a death wish, consider feathering the clutch much more than required; in this case, feathering means to alternately apply and release the clutch to gain extra movement. It's probably unfair for me to make that statement, however, though in viewing the source for this meaning I couldn't help but feel a bit nervous.
Going back to the beginning of this article, you may remember that the Greek pteron means either "wing" or "oar." Where does this connection come from? There is a phase "to feather your oar," which means to turn an oar horizontal above the water as you are moving forward on the next stroke when rowing. Presumably it derives from how the oar throws off water "in a feathery spray," though it does remind me of the use of feather in aviation, "to increase the pitch of the blade." This use of the term is rather comically used in the fifth chapter "Wool and Water" of Lewis Carroll's Through the Looking Glass; poor Alice is commanded to "Feather!" by a rowing sheep after some knitting needles magically transform into oars, without having the meaning of what she is commanded to do explained to her, and nor is the reader.
To "feather your nest" is to make money while taking advantage of a situation, such as being in a particular job. This one appears in the mid-1500's and is a rather well known phrase.
One less well known, I presume, is a feather key. This is from the field of mechanical engineering and means a particular type of key which connects a hub and a shaft. It's also known as a spline.
If you granulate copper by melting it and then pouring it into cold water, those pieces of copper are now called feather shot. I didn't find a whole lot about this on the internet, but apparently it's a thing in metallurgy.
Apparently people who believe in angels have assembled an entire catalog of different spiritual "meanings" concerning feathers based on their color. This is not too surprising, and can perhaps be useful when reading poetry or looking at paintings and using these color assignations to affect your interpretation of what you come across. I'll give just a few examples : a white feather signifies that an angel has your back; a purple feather (i don't suppose there are many of those) means you will soon have a spiritual awakening of some sort; a black feather means you will soon begin to feel better; red feathers indicate seduction in the offing (gasp!); a green feather signifies luck... I wonder how many green birds can be found in Ireland...if a feather has both green and red in it, then it signifies money-making, which I submit is most helpful during Christmas time. I notice that there are no negative meanings to any feather colors in my source, so playing with the colors of feathers appears to be a way of encountering positive feelings. Still, if you ever find a dead raven, and especially a bunch of dead ones, don't go picking them up and collecting their feathers, because the sense of "feeling better" may be preceded by a sense of feeling rather ill, if luck is not on your side.
Author's Note : this essay will appear in my upcoming book, My Cat Breaks Into Vowels, which is available for pre-order.
Sources :
https://www.google.com/search?q=what+does+feather+mean, accessed on 2024-03-12
https://www.etymonline.com/word/feather, accessed on 2024-03-12
https://en.wikipedia.org/wiki/War_bonnet#Ceremonial_importance, accessed on 2024-03-12
https://www.infoplease.com/dictionary/brewers/feather, accessed on 2024-03-13
https://www.infoplease.com/dictionary/brewers/feather-your-cap, accessed on 2024-03-13
https://www.opensourceshakespeare.org/views/plays/play_view.php?WorkID=timonathens&Act=1&Scene=1&Scope=scene&LineHighlight=125#125, accessed on 2024-03-13
https://grammarist.com/idiom/knock-one-over-with-a-feather-and-knock-one-down-with-a-feather/, accessed on 2024-03-13
https://www.britannica.com/biography/Saint-Sebastian, accessed on 2024-03-13
https://en.wikipedia.org/wiki/Martyrdom_of_Saint_Sebastian_(Pollaiuolo), accessed on 2024-03-13
https://blogs.brighton.ac.uk/homer/2020/05/14/how-to-prevent-the-plague-how-to-stop-the-pestilence-can-we-learn-lessons-from-homer/, accessed on 2024-03-13
https://australian.museum/learn/cultures/international-collection/ancient-egyptian/the-underworld-and-the-afterlife-in-ancient-egypt/, accessed on 2024-03-13
https://skybrary.aero/articles/feathering, accessed on 2024-03-13
https://www.youtube.com/watch?v=XDMivP58Smw, accessed on 2024-03-13
https://words.fromoldbooks.org/Brewer-DictionaryOfPhraseAndFable/f/feather-ones-oar.html, accessed on 2024-03-13
https://carroll.thefreelibrary.com/Through-the-Looking-Glass/1-5, accessed on 2024-03-13
https://www.dictionary.com/browse/feather-one-s-nest, accessed on 2024-03-14
https://www.wordreference.com/definition/feather%20key, accessed on 2024-03-14
https://www.merriam-webster.com/dictionary/feather%20shot, accessed on 2024-03-14
https://my.astrofame.com/clairvoyance/article/feathers-meanings, accessed on 2024-03-14