For those of you with Web sites, you probably know what a "host" is. It's a company that provides a location, or address, on the Internet where your Web site resides.
In other words, just like a physical business needs an address, so does a Web site. You can't have a Web site and just "stick it up" on the Web. Unless you want to set up your own server, you have to go through a hosting company who gives you that address, including server space and bandwidth, that enables the search engines and visitors to find your site.