What are the parts of an email address called?

An email address has three parts: the username, the @ symbol and the domain. In hello@yourplumbing.co.uk, the address of your plumbing business, hello is the username, the @ sits in the middle, and yourplumbing.co.uk is the domain.

The three parts of an email address

The parts always come in this order, and you'll see each of them under other names too:

1. Username, also called the local part or email prefix, and informally the email handle.
2. @ symbol, also called the at sign and read as "at".
3. Domain, also called the email suffix.

Without the @, the address isn't valid. With a misspelt domain that doesn't exist, the message can't be delivered, and you get a notice back saying it bounced. A typo can also send your email to someone else, if the mistyped address happens to exist.

The username (local part)

The username is everything before the @. It tells the receiving server which mailbox to put the email in, and it can be a person's name (sam), a role (hello or sales) or the name of your business.

You choose the username when you create an email account. It only has to be unique within its domain: there can be only one hello@yourplumbing.co.uk, but other businesses can use hello@ on their own domains. Shared addresses such as info@ and sales@ are known as role addresses. A role address such as hello@ suits a mailbox that several people in the office answer, and a first name such as sam@ suits mail that only you handle.

Capital letters don't usually matter: in practice, Hello@ and hello@ reach the same mailbox.

Some providers, Gmail among them, let you add a plus sign and a word after your username, such as hello+quotes@. Email sent to that address still arrives in your normal inbox, and you can sort it by the word after the plus. Not every provider does this, so check with yours before you give such an address out.

The @ symbol

The @ separates the username from the domain: it marks where the name of the mailbox ends and the address of the organisation that receives the email begins. Read out loud, hello@yourplumbing.co.uk becomes "hello at yourplumbing.co.uk".

The domain (email suffix)

The domain is everything after the @. It's made up of the name you registered, yourplumbing, and the domain extension .co.uk, a popular ending for UK businesses.

The domain is what gets your message to the right place. When you send an email, the sending server looks up the domain to find the email server that accepts email for it, and delivers the message there.

With a free email service, the part after the @ is the provider's, as in @gmail.com. With your own domain, it's your business name. Customers can see who they're dealing with, and your address stays the same if you ever change email provider.

Create professional email addresses on your own domain, such as hello@yourplumbing.co.uk.

The parts of an email message

The message you send has parts of its own, from the sender at the top to the signature at the bottom.

Sender and recipients

The From field holds the sender: the address of the person who wrote the message, so yours when you're the one writing. It usually shows with a display name, such as Sam Patel, which you set in your email program and which isn't part of the address itself.

The people the message is for go in the To field. Use Cc (carbon copy) for people you want to keep informed, who don't need to act on the message. Use Bcc (blind carbon copy) for people whose addresses the other recipients shouldn't see.

Subject line

The subject line is the short line that tells the recipient what the email is about before they open it, so they can decide whether to read it. Make it specific: "Your quote for the new bathroom" tells them far more than "Hello".

Body

The body is the message itself, and in a business email it usually follows a set order. You start an email with a greeting that uses the person's name, as in "Dear Ms Evans," or "Hello Sarah,", then get to the point and end with a closing line such as "Kind regards". Links and images go in the body as well, and attachments are sent along with it.

Signature

A signature is the block at the end of an email that tells people who you are and how to reach you, so they don't have to search for your number. Writing a good email signature usually means adding your name, phone number and website, sometimes with your logo. Set up an email address on your own domain and use the same name after the @ as on your website.