The relationship between Phoenix, Phoencian, Punic…
I never thought of the words at the same time before. I think it came to me when I was reading something about heraldry.
Argentina = Silvery place
This one occurred to me when I learned the Spanish word (around age 20), which breaks down the same way: des- “un” + -ayunar “to fast.” A good example of how learning another language also teaches you about your OWN language.
Same with “welcome,” which I never parsed out until I encountered the French (bienvenu) and Spanish (bienvenido) equivalents.
Omega and Omicron
Big O: o (mega)
Lil O: o (micro) n
I remember when I started realizing just where all those down-home, folksy slang words came from… especially the sweetly corny “Shucks”, which is a combination of half of two of the most vulgar words in the English language.
One I got from a previous thread on the subject: to “pontificate” is “to assume pompous and dignified airs, issue dogmatic decrees” – you know, like a pontiff.
Here’s a different claim on the etymology of the word “shucks”:
Mind blown.
Two I heard on ***Jeopardy! ***last night:
Acropolis = acro + polis = “high city,” because it’s on top of a hill.
The first two transuranic elements are neptunium and plutonium, since the planets Neptune and Pluto lie, you know, beyond Uranus.
also a German word for lawyer - Advokat which has the obvious connection to advocate.
A German friend once called me a weenie (well, many times actually), but it got me thinking. Weenie as an insult evokes images of a penis because it comes from wiener (as in Frankfurter, which of course, as an aside comes from the German city) which comes from the German word for Vienna, (i.e. Wien). So the word had to travel from the German language to English to be used by a German as an insult.
One I just heard on Millionaire:
Orthopedics = Straightening children’s bones (after they’ve had rickets, probably). I had always assumed the ped had something to do with feet.
just add +itis to any organ name or body part, and you have the name of a new “disease”! Unfortunately, “itis” just means “inflammation of…”
so when you think your doctor is smart because he says, “Oh you have tonsillitis!”. It doesn’t mean they’ve actually diagnosed anything, just described it. “Yes I know my tonsils are inflamed, that’s why I’m here…” substitute bronchitis, gastritis, vaginitis (eww) - all the same story.
The same in Russian.
It wasn’t until I was an adult that I realized carpet wasn’t a portmanteau of car + pet.
Louis Armstrong’s nickname was a portmanteau
Perfect! I like the way you think. And drink. 
So is “he had me over a barrel” a sexual reference? Because it sure seems like one to me (though that thought only occurred to me in recent years).
This doesn’t exactly fit the thread, but I’m going to post it anyway:
As far back as I can remember, I’ve known that hippopotamus comes from hippo + potamus = river horse. But, I never knew why. The hippos that I’ve seen in zoos don’t look anything like horses. In fact, they look the opposite of a horse–slow, sluggish, and fat. Rhinos or elephants maybe, but not horses.
Just recently however I watched the movie The Snows of Kilimanjaro, which includes a cool scene wherein a party of adventurers follow a herd of hippos into a river, spooking them and provoking a hippo stampede. The hippos stick their heads above the water and lumber, and they’re dead ringers for galloping horses, if horses were to gallop under water.
So I’m babbling at the screen, “They’re horses! They’re river horses!” I always knew the etymology, but it never made sense. Until now.
And I had to learn it from a 60-year-old movie.