A "heavenly messenger" in Latin is literally nuntius caelestis. But you may be thinking of the word angelus, which is a borrowing into Latin of the Greek word for "messenger".
Nuntius is messenger in Latin.
From the medieval Latin masculine name Angelus which was derived from the name of the heavenly creature (itself derived from the Greek word angelos meaning "messenger")
The name of the Latin messenger god is Mercury.
Nuntius.
The name Celestine is latin and means heavenly, or the one who came from heaven.
a heavenly messenger http://www.babynameaddicts.com/html/names/female/female_a.html
Uranus is a Latin word- it means heavenly in English
Hermes (Latin: Mercury).
Celeste means "heavenly" in Latin, but it has no meaning in Hebrew.
Hermes (Latin: Mercury).
The root word for messenger is "message," which comes from the Latin word "missus," meaning "to send."
The name Celine is of a Latin origin and it means "The Moon".