S/MIME in internet technology stands for

S slash MIME expands to Secure Multipurpose Internet Mail Extensions, a standard for signing and encrypting email messages.

The word after Secure is Multipurpose, not Multimedia, since it extends general mail formats and not just media.

It begins with Secure, not Simple, because its whole purpose is security.

It begins with Secure, not Standard, so that expansion is wrong.

It builds on MIME, which lets email carry text, images and attachments.

S/MIME uses public key cryptography to protect message contents and verify senders.