Floors in the Middle Ages were dirt covered with straw for insulation and other reasons.

Threshold = thresh (straw) + hold (a piece of wood across the front doorway to stop the thresh from spilling out)

I don't think anyone has mentioned "helicopter" yet. It's not heli and copter like you might think. It's helico like helix meaning spiral and pter like pterodactyl meaning winged.

Thought of this while looking up where the term "bootleg" comes from. Turns out people used to conceal flasks of alcohol inside the leg of a tall boot to hide them from authorities during Prohibition.

Similar one for the term "shotgun" when you call the front passenger seat. That's where the guy with the shotgun sat when goods and people were transported by horse-drawn wagons. Also, a funny sidenote: in Finnish language it's commonly refered to as "pelkääjän paikka" which translates to "seat for the one being afraid"

Edit: Goodbye - God be with ye

I've always found it fun how in Germanic (and Romance) languages, we still honor the old gods when it comes to the days of the week. Like wednesday being "Wodan's/Odin's day" and thursday being "Thor's day". I wonder how many devout christians realize this.

I also think the etymology of the German word "Buchstaben" (letter, as in a,b,c) is pretty interesting. It literally means "beech rod" and goes back all the way to Germanic tribespeople carving runes into rods made from beechwood.

The word "nice" used to mean "stupid." It derives from the Latin "nescio" (translated: "I don't know") and carried over into old French. At some point, it came to be associated with generosity, the assumption being that someone stupid is too innocent or naive to be selfish.

It then got carried over into middle English, and the connotation for stupidity got dropped, making it so that the word meant "kind," as opposed to "stupidly kind"

The abbreviation ‘lbs’ for ‘pounds’ comes from the Roman ‘libre pondo’ meaning ‘a pound by weight’.

This is also the reason the symbol for Libra in the zodiac is scales (Libra is the only sign represented by an inanimate object).

I just learnt this today, and I can’t believe I never noticed before now that ‘lbs’ for ‘pounds’ is weird. I always just mentally glossed over it.

"Helicopter" isn't heli - copter

It's helico - pter.

Helico: Greek for helix or spiral.

Pter: Greek for wing, like a pterodactyl.

The word "tycoon" was brought into English from the Japanese word taikun (大君), one of the words for "lord." The Japanese word itself would have been brought over from China a long time before.

In Latin sinister means left (as in the direction), but later it also meant evil or unlucky. That led to the Old French senestre and sinistre, meaning false or unfavorable. Then finally the English sinister meaning malicious.

The etymology for left (especially in reference to handedness) in multiple languages is actually pretty discriminatory.

Boondocks, meaning a remote place, entered English from the Tagalog word bundok, meaning mountain. American soldiers returning from occupying the Philippines introduced it in the early 20th century.

Buckaroo comes from the inability to pronounce/ the mispronunciation of the Spanish word for cowboy, Vaquero.

The word "standard," meaning "level of quality" or "rule" evolved from the physical battle flag on a pole, as in "standard bearer." So for things like standardized lengths of measurement, you could say "we follow the king's standard for what a foot is," which was a metaphor for following the king's rule on what that length was. That further stretched into a level of quality or conduct that needed to be achieved.

This might be obvious to some, but I only recently realized. A standard was originally a flag on a poll, meant to be visible across a battlefield as a direction for all to follow.

Denim= De Nîmes (from the city of Nîmes)

Jeans = Gênes , the French weird for Genoa.

The cotton weave, indigo dyed cloth originated in Genoa, and in France the main production centre was Nîmes.

So 'denim jeans' is both a tautology and a contradiction

Mayday comes from French m'aidez which is pronounced similarly, and simply means "help me!"

'Bully' used to mean good friend. There's a scene in Shakespeare (who else?) where he talks about someone sending his bully boys to teach someone a lesson, meaning he sent his close friends. But, over time, people took it to mean his thuggish friends and so the word's meaning shifted.

This isn't a common term but it's something I recently learned that's kind of funny - the country Timor-Leste is named from the Malay word timur, meaning "east", and the Portuguese word leste, meaning "east". So it's literally "East East".

“Son of a gun” is from when sailing ships would come into port. The sex workers would row out to them and have sex with an entire gun crew.

When the kid was born they didn’t know who the father was so he was a “son of a gun” aka a bastard.

Not a "common" term, but the word Neanderthal comes from the name of a river valley in Germany where neanderthals were first discovered. The valley in turn is named after a Calvinist hymn writer named Joachim Neander who often visited the valley and used its natural beauty as inspiration for his hymns. I find the unintentional synthesis of two ideas that many people would otherwise regard as incongruous to be beautiful in a weird way.

In the phrase "to get off scot-free", the word scot has nothing to do with Scotland or the Scottish. It's an Old English word meaning fine or penalty.

I once overheard a tour guide confidently tell a group of visitors to Edinburgh that the phrase was coined after one of the "grave robbers" Burke and Hare became a witness for the prosecution and was released. Burke and Hare were actually Irish, and they were murderers.

In English, the words for many animals (chicken, cow, sheep, deer, pig) are derived from proto-germanic, while the word for their meat (poultry, beef, mutton, venison, pork) is French derived.

Bonus: A good chunk of river names are just "River" in the local language. So many River Rivers from newcomers adopting the river names, not knowing it just means "river"

Apothecary

Ancient Greek for "storage shed".

Either „tea“ or „cha/chai“ exist in some form in virtually every language that has encountered tea, and the distinction between which was adopted generally has to do with whether it was first traded with the country by land (cha) from China or by sea (tea) from Malaysia.

Snafu and Fubar are WW2 acronyms used as slang, there are many other acronyms in the same family, and new ones that have been added since.

Radar is also a WW2 acronym.

Admiral comes from Arabic "amīral". "Amir" means king, prince, chief, leader, and "al" is the definite article, in English "the" (compare algebra or alchemy).

So admiral means "leader of the", the Arabic for "leader of the sea", Amīr al-Baḥr, was too long to survive the whole game of telephone.

In Russian the days of the week are mostly numbers, e.g. Tuesday is the second day, so Tuesday is Вторник, which comes from второй (second) and the suffix -ник for day. But Monday is not перник as you would expect (первых + ник), instead Monday is Понедельник. This is short for после (after) не (not) делать (doing) -ник (day), i.e the day after not doing anything (Sunday).

In Finnish a tietosanakirja is an encyclopedia, this is a composed word made from tieto (knowledge) and sanakirja (Dictionary). But also sanakirja is a composed word made out from sana (word) and kirja (book). So an encyclopedia is a book of words of knowledge.

There's a restaurant here called Chai Pani and I never understood why they'd name themselves that (literally "tea water"), but then my Indian father-in-law explained to me what the term is actually used for. It's used if someone wants you to bribe them. It's kind of like asking for some money for coffee - "I need money for tea".

Barbecue comes from Spanish barbacoa which comes from Taino language used in the Caribbean region. Natives there invented barbecue, the Spanish took it to the old continent and it spread from there.

Chocolate comes from náhuatl language used by Mexica people. Xocoatl, from xoco 'sour' y atl 'water'.

Coach (as in bus) comes from Hungarian kocsi. They invented a type of horse pulled carriage which later gave the name to the coaches we know from westerns and then to busses and cars. Coche (car in Spanish) has the same etymology.

The British insult "tow rag" or "toe rag", referring to a contemptible and worthless person, is named after the nautical precusor to toilet paper:

Back in the days of sailing ships, the sailors did not have toilet paper. What they did have were rags. Cloth rags known as "tow". After having completed their daily evacuations, sailors would engage in ablutions using a rag. This rag was then tied to a rope and dragged behind the ship in order to clean it (or them).

https://snowbirdofparadise.com/2020/04/02/the-tow-rag-explained/

Copacetic -- it was just invented as a fake word to mean OK, all clear

In archery, arrows have three feathers (in a Y shape) rather than four (+) so that it can slide past the bow without damaging the feathers or the bow. This means that the arrow can be nocked either the right way (with the leg of the Y away from the bow) or the wrong way (with the leg of the Y towards the bow).

In medieval Europe, the arrow would be nocked with the bow held horizontally. To make it easier for archers to quickly and easily nock their arrows, the feather to go away from the bow (pointing upwards) was a different color, and came from a cock (rooster). So when drilling new archers, if they nocked the arrow the wrong way, the instructor would shout "Cock Up!".

This came to mean a mistake.

Every form of the word "check" comes from a Persian word, shahmat, which means "the king dies". This is from the earliest known games of chess, and that specifically got brought into English as "checkmate".

"Great" used to mean "big" rather than "really good". Which is why the largest of the islands in the North Atlantic archipelago is called "Great Britain".

Proto-slavic used the root "dn" (дн) for water, which explains river names such as Dnipro (Дніпро,Днепр), Danube (Дунай/Donau), Don (Дон), Dnjester (Днестр, Дністро).

The "mast" in "mastodon" is the same one as in "mastectomy".

"The term "mastodon" comes from Greek roots: "mastos" meaning "breast" and "odon" meaning "tooth," referring to the nipple-like projections on the mammal's fossil molars. The name was coined by French naturalist Georges Cuvier in 1806."

The term "snorkel" is related to the German word for snoring.

Back in WW2, U-boats (and pretty much all submarines) needed to surface so that they would be able to run their diesel engines in order to charge their batteries because diesel combustion requires oxygen. One German scientist developed a way to get air without having to surface the boat. As this was a very big tactical advantage it was, obviously top secret. In order to not give away what it was, he referred to it by the sound it made i.e. that of someone snoring.

EDITED with new info from helpful Lemmings.