What is it?
A domain is the name of an internet website or an online location, and can include letters, numbers and a dash, but no other characters. It is also known as an internet or website address, and is what you see after the prefix www, which stands for world wide web.
A URL is an entire internet address, and can include a domain name. For instance, www.wikipedia.org is a domain name and a URL, whereas http://en.wikipedia.org/wiki/School is another address within Wikipedia, and so its own URL.
Domain extensions refer to the ending of a domain address, such as .com.au (commercial websites in Australia), or .org (for organisations, such as charities, where business will not be conducted).
How does it work?
Domain names are a substitute for the IP address, a series of numbers that refers to the server that hosts the domain.
Why is it useful?
Domain names are generally much easier to remember than a string of numbers.
What do you need to keep in mind about domains and your children?
Remember that domain names must be typed correctly. While some search engines will correct some spelling mistakes, it's common for unscrupulous people to take advantage of mistyped domain names to trick people. This is known as "typosquatting" and can lead to malware or even fraud. An example is www.yuube.com which is designed to look like YouTube.