1A letter or note written to someone to convey feelings or information; unlike email, it is often handwritten on paper.
友達に長い手紙を書いた。
I wrote a long letter to my friend.
手紙がポストに届いていた。
There was a letter in the mailbox.
久しぶりに母に手紙を送った。
I sent a letter to my mother for the first time in a while.
手紙の最後に「またね」と書いた。
I wrote 「またね」at the end of the letter.