“School supplies” is the term used for someone in school; otherwise, the term used is “office supplies.”
 
“is growing up saying office supplies instead of school supplies” was posted on Twitter by kelsey on December 23, 2015. “Adulthood is shopping for office supplies instead of school supplies.#Adulthood #AllGrownUp” was posted on Twitter by Mallory on February 6, 2016. “You know you’re an adult when you think of pens and papers as office supplies instead of school supplies” was posted on Reddit—Showerthoughts on January 30, 2021.
 
         
Twitter
Sara Campeau
@SaraCampeau
1st September not going back to school in 19 yrs! Buying office supplies instead of school supplies #wowtimeflies
12:11 AM · Sep 4, 2012·Twitter Web Client
 
Twitter 
Doug
@DougEatDoug
Pretty terrified that in a few short years I’ll be saying office supplies instead of school supplies.
5:11 PM · Nov 26, 2012·Twitter for BlackBerry®
 
Twitter
Corey schnur
@CoreySchnur
Makes ya feel old when you have to go buy office supplies instead of school supplies #imoldnow #imgrown
9:03 PM · Jun 4, 2014·Twitter for iPhone
 
Twitter
Maureen
@mau_reeny
I may have graduated but I’m still calling it “school supplies” instead of “office supplies”
11:30 AM · Feb 8, 2015·Twitter for Android
   
Twitter
kelsey
@comebackoftheyr
is growing up saying office supplies instead of school supplies
10:01 PM · Dec 23, 2015·Twitter for iPhone
 
Twitter
Mallory
@whovienne88
Adulthood is shopping for office supplies instead of school supplies.#Adulthood #AllGrownUp
4:05 PM · Feb 6, 2016·Twitter Web Client
         
Twitter
ellie
@ellieesays
the only adult thing I do is call all of my pens and sticky notes office supplies instead of school supplies.
8:35 AM · Aug 14, 2016·Twitter for iPhone
 
Twitter
the perpetual college student
@alabamaredheadd
And yes, I realize one day there will hopefully be a time when I start calling things office supplies instead of school supplies. One day.
6:35 PM · Apr 25, 2017·Twitter for iPhone
 
Twitter
Jamie Rosengard
@jamieeros
I’m turning 30 next month and I still call them school supplies instead of office supplies.
1:58 PM · Aug 3, 2018·Twitter for iPhone
   
Twitter
and the bad seeds
@nickcavge
does everyone remember the day they first purchased office supplies instead of school supplies?
12:41 PM · Sep 10, 2018 from Los Angeles, CA·Twitter for iPhone
 
Reddit—Showerthoughts
Posted by u/windwakin January 30, 2021
You know you’re an adult when you think of pens and papers as office supplies instead of school supplies.