Rather, it’s taken from the Latinin re,which means “in the matter of.”
They may think the message is a reply that belongs to an email thread they haven’t seen.
It means “reply.”
It’s common for cold-solicitation business-to-business emails to start with areto exploit this ambiguity.
To prevent confusion, don’t insert RE: in a subject line.
The fact of the subject line itself implies that this is what the message is “regarding.”
Instead, allow RE: to appear when you reply to an email message sent to you.
