The operating system's mail application was updated with MailDrop, which encrypts and routes large attachments that might be rejected by some mail servers through iCloud.
Chicago Tribune(Jun 02, 2014)
n a drop where mail can be deposited
Hypo|Hyper
letter box, mailbox, postbox
public box for deposit of mail
pillar box
a red pillar-shaped letter box
drop
a central depository where things can be left or picked up