Le Vieux Lapin introduces us to “Cat and Girl” and says:
In ancient times, the word “polymath” described someone with great experties
in multiple fields. Like so many other words, though, “polymath” has been
devalued in the age of social media. What does it take to be a polymath
today? Dorothy Gambrell’s Cat of Cat and Girl seems to have figured it out
While I am familiar with the word “polymath” I don’t normally run across it every day. But — as these things work — it happens that the next day I ran across this tweet:
P.S. Le Vieux Lapin adds “Cat needs to eat his ice cream cones faster.”
Comics I Don't Understand 
A bit off topic, but the cat’s soggy arm reminded me of my niece reporting on a road trip down the West Coast* of the US this summer with her family: her daughter (aged 4) was rescued by a homeless person “who kindly offered us napkins after Willow decided to eat her cone first and leave the ice cream for after”.
*They live in Seattle and got to San Diego and back.
When I was a grad student in the math department, I heard ‘polymath’ several times, always in the sense that EditorM gave, of someone who is an expert in many fields. It confused me mightily until I looked it up.
(Chak? Is that you? What are you doing up at 6 in the morning?)
(I couldn’t sleep, and the ice cream in the freezer was calling my name.)
It was so hot in NYC this summer that every time I got Mr. Softee, usually from the same guy at Union Square, it would run down my arm. The ice cream guy would only give me one thin napkin. And I would tell him, ” You have to give me more napkins, this thing is melted down my arm before I leave the truck!” He just laughed. Gave me some napkins and proceeded to raise the prices, as Mr. Softee seems to do each year.
Chak, the compact definition of polymath , as well as the whole italicized passage, are from Le Vieux Lapin (and not me).
However, I did share your experience on first learning the term, of confusion that -math here meant any form of learning, not just mathematics. One kind of wanted to say “Yes, So-and-so is a polymath, they’re good at algebra and geometry as well as number theory….”
A little digging on Etymonline comes up with the same root in IE appearing in both these words (via Greek it seems).
*mendh-
Proto-Indo-European root meaning “to learn.” It forms all or part of: chrestomathy; mathematic; mathematical; mathematics; opsimathy; polymath.
Though aftermath has a different one, related to mow
(See https://www.etymonline.com/word/*mendh- for that bit printed with bold and/or red words)
I thought it was arithmetic for tropical birds.
(crickets)
There were a lot of polymaths at my high school. One for instance was expert at football, smoking, getting the girls into bed with him, and skipping classes without being noticed.
For a period of time, my .sig. on usenet was:
—
If televison’s a babysitter, the Internet is a drunk librarian who
won’t shut up.
— Dorothy Gambrell (http://catandgirl.com)
To paraphrase Tuco, “When you have to eat ice cream, eat. Don’t talk.”
Years ago I learned to get ice cream in cups instead of cones. The larger scoops will still run down the side of the cup given the chance, but it still seems more manageable than running down a cone.
I have a big heavy beard, and I agree that for ice cream, cups work better than cones.
Grawlix – And as one ages and the teeth don’t work as well on the cone – a cup is better.
Right now having our third meal of the day – late night snack – which is chocolate ice cream in a glass cup tonight. If Robert tried to push it all into a cone – the cone would break.