Eiderdown from Pink Floyd’s A Pillow Of Winds. Was this word in another Floyd song as well?
psilocybin – from "I’m In Touch With Your World by The Cars
Yes, in “Flaming” from their first album.
My ghetto vocabulary is almost exclusively from rap songs. Where would I be now without the likes of:
‘back’
‘hollah’
‘krunk’
‘badunk-a-dunk’
‘cronic’
How could I describe my world of rollin’ wit hommies whilst sippin’ on gin an juice?
Incidentally, I consider that to be one of the most beautiful words in the language.
To answer the OP, I learned “trolling” and “striper” from Billy Joel’s Downeaster Alexa. Previously I had thought that trolling only meant screwing around on message boards 
“septuagenarians”
New Age Girl, by Dead Eye Dick, from Dumb and Dumber soundtrack
DudleyGarrett
Darn you, I was going to mention “gavotte”. 
Another word from a Carly Simon lyric - eiderdown. (“After the Storm”)
That makes three songs using that rather obscure word.
Both from Tom Lehrer’s Alma
Her lovers were many and varied
From the day she began her beguine
and
Gus died, and her tear drops were copious
She cried all the way to the altar
Not me, but my brother- “travesty” -“The Wall” from Kansas’s LEFTOVERTURE.
I’m sure he knew the word, but that song triggered his frequent use of it.
They also use that word in “Julia Dream”, which was originally a b-side but later appeared on Relics. I don’t think I’ve ever heard that word used outside of those three songs.
Proselytized (I’m sure I spelled it wrong) from Blood Sweat & Tears “I Can’t Quit Her”
The boys of Bad Religion also need to step up to the plate for:
enthalpic (Graffin, “The World Won’t Stop”)
anechoic (Graffin, “Delirium of Disorder”)
grandiloquent (Bentley, “The Positive Aspect of Negative Thinking”)
…and probably a slew more that I can’t think of right now. When I was 19, that shit blew the top of my head clean off. 
Nonchalant, from the Stones’ “Backstreet Girl”
Now that you mention it, I actually learned that word from yet another TMBG song, “She’s an Angel”.
Contrary to how it may appear, TMBG is not the source of my entire vocabulary.
LilShieste
You knew monotreme and allotheria before hearing Mammal?
A non-Pink Floyd song that uses “eiderdown” is Roxy Music’s “Mother of Pearl.”
I learned cyclothymic from King Crimson’s “Three of a Perfect Pair.”
You know, you’re not helping my case here…
Oh well, why fight it:
Argonauts. “After killing Jason off, and countless screaming Argonauts.” - Birdhouse in Your Soul, by They Might Be Giants
LilShieste