A tree structure describing the relationship of your accounts and services to your divisions, departments, or cost centers. Hierarchies consist of individual nodes connected together in parent-child relationships.
In Internet usage, a host is any computer that has full two-way access to other computers via the Internet. Each host has a unique IP (Internet Protocol) address. The term also describes a computer equipped with a server that delivers, or "serves," the pages of a web site to a browser that requests them. Companies that provide this service are also called hosts; the service is called hosting. For large organizations that use complex mainframe computers, the host is the mainframe itself (now usually referred to as the large server). In this context, the mainframe has intelligent or "dumb" workstations attached to it, to which it provides various services. In other contexts, a host is a device or software program that provides services to a smaller or less capable device or software program.
While it sounds like something to do with school homework, a history list is actually a drop-down menu in a Web browser that contains a log of the document titles and URLs you have visited during your Web session. It's a convenience feature that lets you jump back to where you've been without having to click repeatedly on the Back button or retype Web addresses each time.
The computing protocol used to transmit and receive all data over the World Wide Web. When you type a Web address (aka a domain name or URL) into your browser, you're actually sending an HTTP request to a Web server for a page of information (that's why Web addresses technically begin with "http://" -- although some software packages add this code automatically for you).