Communication mailed with no envelope (8)

I believe the answer is:

postcard

(Other definitions for postcard that I've seen before include "Holiday communication" , "It's sent without an envelope" , "Limited communication" , "Brief message" , "Bringer of message" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.