Quote Originally Posted by Hooper View Post
I was taught that such things would be hyphenated when used in an adjective sense, otherwise not. So, depending upon its usage, you will see it both ways. Here's a snippet from a proof-reading forum:
... a hyphen is used to join two words into effectively one word, when used adjectivally. It avoids ambiguity where it might exist. E.g.,
A copper coin dispenser
A copper-coin dispenser
A copper coin-dispenser
So, a thank-you note would be correct usage, as would thank you gentlemen.

Then again, I'm a "USAnian"
YMMV
This initially narked me, but I let it slip. But Hoopers post brought it up again. You see i'm a stickler for grammar at times. So I did a bit of research on this (an American) grammar site.

'Thank you' is a verb. Xman said 'thank you all' so the thank you in question was a verb.

'Thankyou' is a noun. Had xman said 'many thankyous to you all' that too would have been correct.

'Thank-you' is a hyphenated compound noun. Had xman said 'A thank-you to all' then that too would have been correct since in that usage it would have been a noun.

'A thank-you note' IS correct since a thank-you note is a noun.

However, in his original usage he used it as a verb and not as an adjective, so only the first form is correct.

"Then again, i'm a UKnian"




NB: In checking my grammar in this post the only thing the SITES spell-checker doesn't like is 'thankyou'