Noun
certified mail (uncountable)
(US) First class mail that provides the sender proof of mailing and a delivery record.
None of the Shanti clinicians responded to repeated interview requests by phone, email or certified mail. Source: Internet
If you desire to assert a claim against Company, and you therefore elect to seek arbitration, you must first send to Company, by certified mail, a written notice of your claim (“Notice”). Source: Internet
Similarly, if you choose to register through the mail, pay the extra money for certified mail to confirm the recipient receives your form. Source: Internet