"Thank you": verb
"Thank-you notes": modifier
"A thank-you": noun
"Many thank-yous" or "many thank you's": plural noun
I always get a lot of questions about hyphens when I do my AP style webinars, and it’s not surprising because hyphens can be confusing.
When does ‘thank-you’ need a hyphen?
When “thank” is a verb, you don’t need a hyphen
- We thank you for inviting us to your holiday Zoom party.
- Thank you for the gift.
But when “thank you” is a modifier or a noun, then it takes a hyphen.
I wrote a thank-you note.
For example, in “I still need to write a thank-you note,” you use a hyphen in “thank-you” because it’s modifying the noun “note.”
A thank-you is in order.
And you also use a hyphen when “thank you” itself is a noun, as in “Sending you a hearty thank-you for the presents.”
The plural of ‘thank you’
Nouns can be plural, so how do you make “thank you” plural?
Well, it still takes a hyphen, but beyond that, it’s a little tricky because style guides say different things. You always add an S. (It sounds like “thank-yous,” as in “I still owe people many thank-yous.”)
The Chicago Manual of Style says to just add the S at the end: “thank-yous” with a hyphen.
But Associated Press style adds an apostrophe before the S: “thank-you’s.” It’s a little weird, but it’s not the only case like that.
It reminds me of “dos and don’ts,” which Chicago writes without an apostrophe in “dos,” and AP writes with an apostrophe in “do’s.”
So how you write “thank-yous” depends on which style guide you follow. If you aren’t required to follow a specific style guide, you can use whichever style seems best to you. Just pick one and be consistent.
‘Unthank’
If you’d like a bit of word trivia, “unthank” is an obsolete word in English. It was both a verb and a noun. You could unthank someone—rescind your thanks—and as a noun, “unthank” meant something that caused offense or displeasure or it could mean a curse. It shows up in Chaucer’s “Reeve’s Tale” in this line about a horse that got loose:
“Unthank come on his hand that boond hym so.”
which is translated into modern English as
“Curses come on his hand that bound him so,” or “Curses come on his hand that tied him so carelessly.”
So get on those thank-you notes. If you have reservations, you can always unthank them later!
Remember that “thank-you” takes a hyphen when it’s modifying a noun, like “notes” in “thank-you notes”; and it takes a hyphen when it’s a singular or plural noun, as in “I hope you don’t have too many thank-yous left to write.”