thank-you note

The recreation therapy department afterward sent the club a thank-you note.

Fans of the new system should drop a thank-you note to Justice Roberts and the four other Supremes who decided Citizens United.

Why would colleges value something as simple as a thank-you note so strongly?

(Clinton sent a thank-you note, which the actor framed and put up in his home).

I meant this to be just a short little thank-you note—but when I get started I seem to have a ready pen.