letter
US /ˈlet̬.ɚ/
UK /ˈlet̬.ɚ/

1.
2.
信
a written, typed, or printed communication, especially one sent in an envelope by mail or messenger
:
•
I received a letter from my aunt yesterday.
我昨天收到了我姑姑的一封信。
•
She wrote a long letter to her friend.
她給她的朋友寫了一封長信。