Word(s) that only ever appeared in one (hit) song, ever.

I won't quibble, but it doesn't quite feel like an apples-to-apples comparison...

How about "serpentine," from "Welcome to the Jungle" (#7 on Hot 100)?

"Serpentine Fire" by Earth, Wind, and Fire (#13 Billboard pop chart)

If you're going all the way up to 100, then Wire's "Outdoor Miner" got to No. 51 and has 'serpentine' too. And 'silverfish'.

I don't consider that a hit song though.

Yeah I feel like it should at least be in the, well, Top 40 to qualify as a "hit"

(btw I appreciate and am awed by Josefa's instant song knowledge!)

oh thank you

Backing up a bit, I think "nicety" is a good submission. The word has probably been in songs before (hits, I don't know) but not in the way that Michel'le is using it, which is as an adjective meaning nice + nasty. Which puts it in the category of words/usages that were coined just for one song. Another one like that is the verb "surry" which was coined by Laura Nyro just for the song "Stoned Soul Picnic."

I saw 'nicety' and quickly thought of Massive Attack's 'Safe From Harm' but that's niceties anyway.

I submit for consideration, from Another Bad Creation's 'Iesha', the word 'monkeybars'. Possibly also the word 'Nintendo'. I was tempted to go even further and include 'Cheerios' but then I remembered that it also appears in Al Jarreau's 'Mornin''.

"Nintendo" is a key line of American Hi-Fi's "Flavor of the Weak," a US modern rock hit in 2001.

do-lang do-lang do-lang

Also "Super Nintendo, Sega Genesis" in "Juicy," probably the highest-profile use.

All right, but I'm doubling down on 'monkeybars'.

https://www.lyrics.com/lyrics/monkey%20bars

Those are certainly some search results.

Don't wanna be your monkey bars
Fall in, fall out

9 years ago today, @ladygaga's "Born This Way" debuted at #1 on the Hot 100.

It became the first #1 song in history to feature the words "gay, lesbian, bi, transgender" in its lyrics and the chart's 1000th #1 single overall.

— chart data (@chartdata) February 26, 2020

is it also the first #1 song in history to feature the word "chola"?

(unrelated pet peeve about tweets like this: 'today ___ years ago' always really means 'on the chart dated today minus ____ years', which is rather different indeed. billboard's charts have always been post-dated: "born this way," for example, was actually revealed to have reached #1 on feb. 16th, 2011 -- not feb. 26th, which is the date indicated on that week's chart.)

In "My True Story" by the Jive Five I've always heard the opening couplet as "...about two lovers that I knew well," but many online sources give the line as "that I bewail," which is actually how I now hear it. (Although it seems if one internet source gets a lyric wrong, a billion others pick up that error.)

https://www.youtube.com/watch?v=glOMdK8gfbo

10cc have a few of these:

bullhorn / padre / slugs ("Rubber Bullets)

Milton (as in John) ("The Dean and I")

Getty/ Rothschild/ Howard Hughes ("The Wall Street Shuffle")

Crosby (as in Bing)/ toupees ("Silly Love")

minestrone/ parmesan/ lasagne/ constipated/ Pluto/ Pisa/ crepe suzette ("Life Is a Minestrone')

Bullhorn = "I Don't Like Mondays"

Padre = "Green Green Grass of Home"

Indeed!

had to check, but sadly Weird Al's "Lasagna" - which also features "minestrone"! - did not chart.

Getty is also in "Last Child" by Aerosmith (#21 in 1976)

"Puttin' on the Ritz" may be the only one with "spats."

― Darth be not proud (Ye Mad Puffin), Friday, December 15, 2017

I feel like that song must have a few others as well. “Cutaway (Coat)”? “(Gary) Cooper”?

re: "slugs," so weird to realize "Teenage Lobotomy" was not a single. not that it would have been a hit anyway, but its ubiquity/significance today certainly outstrips that of "Rubber Bullets."

"Baccalà" in Rosemary Clooney's "Mambo Italiano"

It's a pity "The Worst Band in the World" flopped for 10cc as that had 'dharma bums' in the lyric.

"abacinate" - Slayer, Angel of Death

That’s not a hit song(!)

oh please it was even on South Park

I don't recall ever hearing the word 'unfettered' in anything other than 'Free Man in Paris'.

'Kegels' in "WAP"

Didn't Chuck Berry... no.

"Whomsoever" in Soundgarden's "Fell on Black Days."

It is also on the title track to the best-selling LP of all time

*smacks forehead*

Whomsoever be starting something
Whomsoever be starting something

The doggone girl is whomsoevers.

"Huarache," in "Surfin' USA," The Beach Boys

Although maybe this was a hit and I missed it:
https://www.youtube.com/watch?v=9S0ONyRctyE

gonna be a huarache tonight

“Huarache Raccoon”

“In Every Dream Home a Huarache”

here comes the story of the hua-ra-che

“amethyst” in Wang Chung’s “Dance Hall Days”

xp huarache comes into Maria Muldaur's "Gringo en Mexico."

I had never heard Prefab Sprout before the other day, but apparently I have a very word-for-word memory for lyrics quoted in ilm threads, because I was getting my hair cut a few days ago, heard the word "infrared" in the song that was playing in the salon, and thought, "Ah, this must be 'Faron Young' by Prefab Sprout."

"Naugahyde" in "Randy Scouse Git" by the Monkees, or "Alternate Title" as it was called on the UK where it was a number 2 hit.

*in the UK