TV series example of the word

The Big Bang Theory Season 1, Episode 11
I guess I owe the Betty Crocker Company a letter of apology.

The Big Bang Theory Season 6, Episode 19
I'm really curious what's in that letter.

Game of Thrones Season 7, Episode 7
Why did she unearth the letter Cersei made you write?

Game of Thrones Season 7, Episode 6
What are you going to do with that letter?

Game of Thrones Season 2, Episode 6
This letter detailing our infantry movements