mailpiece noun1 •(US, Canada) (countable) A piece of mail, that is, an item of (physical) mail; especially, an item of flat envelope form factor as contrasted with an item of package form factor.You have 0 mailpiece(s) and 1 inbound package(s) arriving soon. [U.S. Postal Service Informed Delivery email of the 2020s] formsmailpieces
