Missive (noun)

A written message, especially a formal or official letter.

Origin:

Derived from the latin word "mittere" meaning "to send".

Examples:

1. The queen sent a missive to the ambassador requesting a meeting.
2. I received a missive from my lawyer regarding the case.
3. The company sent a missive to all of its employees announcing the merger.
4. The artist received a missive from the gallery inviting her to participate in the exhibition.
5. The missive was written in a formal and polite tone, requesting for a peaceful resolution.