What do you call the ¶ symbol? One name is pilcrow, but the name alinea, so obscure that it's not even in OED, popped up in an remarkable news article [quoting; elipses omitted].

"The ¶ has long been used to mark the start of a new paragraph. Called an alinea, the symbol connotes a break from the previous chain of thought—a new chapter.

Alinea is the name that celebrated chef Grant Achatz chose for the restaurant he opened in 2005. It was a fitting choice. Achatz reinvents his menu, rewriting his customers' dining experience, each season.
● In May 2005, [a] critic said, "Alinea is the most exciting restaurant debut Chicago has seen in—well, maybe ever."
● In 2006, [a] magazine named Alinea the best restaurant in the country.
● In 2007, it was named the 36th best restaurant in the world.
● In 2008, it jumped to 21st.
● Sunday night Achatz, at age 34, won the James Beard Award as the top chef in the United States."

And here’s the kicker: He “managed the feat after losing his sense of taste. In June 2007, Achatz was diagnosed with stage IV tongue cancer. That's as bad as it gets—there is no stage V. By October, his sense of taste had vanished.

Still, he worked. He dreamed up new dishes. He experimented with ingredients. And he relied on his sous-chefs to calibrate the flavors and finalize the balance of dishes he couldn't taste. We'd venture that many people who have never unfurled a napkin at Alinea are cheering Grant Achatz.”

I call it a paragraph mark because if I used the term pilcrow I'd have to gloss it.

quote:

alinea

From Wikipedia I learned it's from Latin a linea. Alinea is not in the OED Online, but a (prex 1) and linea are. Linea is an anatomical word, but the etymology refers you to line.

From symbols.com I found this and this.

I had always wondered if there was a word for the number sign (#). I found my answer nearly 5 years ago when wordcrafter said it was called an octothorpe (or octothorp) and links to World Wide Words. Quinion gives a number of reported origins. He concludes that "there is no corroborative evidence for any of these stories." But it's an entertaining read.
Here's the "origin" I like:

A second story says that it is a whimsical creation based on the idea that the symbol looks like a village surrounded by eight fields. Thorp is the Old Norse word for a village, which appears in many English place names, such as Scunthorpe or Cleethorpes, though it’s not known in North America. This is possible, though perhaps a little stretched.

Yeah, far-fetched I know, but I still like it. It seems almost like a modification of the Japanese kanji for "rice field," 田.

Read the Wikipedia article about the number sign. Notice the table of symbols on the right.