The term "email messages" refers to electronic mail or email, which is a method of exchanging digital messages between people using computer networks. Emails are typically composed of two parts - the header and body. The header contains information such as sender's address, recipient's address, subject line, date, and other metadata related to the message. The body contains the actual content or text written by the sender. Email messages can be used for various purposes like sending personal communications, conducting business transactions, sharing files, etc.