Email is e-mail, which stands for 'electronic mail'.

This means that you don't  have to hand-write or print out a 'hard copy' of your message or letter on paper.
You don't  have to write an address on a paper envelope.
You don't  have to stick a stamp on, drive or walk to the nearest mailbox and post your letter.
And you don't  (really - this is the best bit) have to wait days for your letter to get there, or pay more to send a letter overseas.

Email is:

• typed into a message window on the computer screen
• a message which includes the email address  of the person you are 'sending to'
• a message which also includes your own 'reply-to' email address  (if you ever want anyone to write back!)
• sent and received through your modem connection to your Internet Service Provider, whose mail server computer is in turn connected to the rest of the Internet
• incredibly cheap: you pay for your local phone call to connect to your local Internet Service Provider, then you pay your ISP the agreed amount per hour while you are connected ... email messages are usually very small files (not cluttered up with formatting  junk, pictures or other files stuck onto them) so you can send or receive an email message in seconds!