A favicon is a small icon image that is associated with a specific site, usually containing the site logo or a variation thereof, like the small "W" icon used by this web site. The favicon is saved as "favicon.ico" and uploaded to the server along with the rest of the files that make up the web site.
The favicon is displayed in the title bar of the browser. If you are using a tabbed browser, the favicon is the small picture on the tab, next to the title of the page.
When a company or entrepreneur identifies a potentially lucrative new idea it works at maximum speed to be first to market. This does not necessarily mean launching it first, but rather being the first to gain users/customers and take a big market share in the absence of any significant competition.
In the context of web site design, a fixed width layout means that the width of the site is fixed to a specific pixel value, as opposed to a fluid width layout where the site width is specified as a percentage. The benefit of a fixed width layout is that the site content is always displayed the same, regardless of the user's monitor resolution. This gives the web designer a bit more control over the final look of the site.
A function of HTML where the user enters data into form fields and usually sends the form using a "Submit" or "Send" button. The search box at the top of this page is an example of a form. It contains one text box where the user types the search term(s) and a search button which sends the search parameters to a PHP script.
Form validation (or more correctly, form field validation) forces a user to fill out all required fields in a web form. The validation is typically done in PHP where the developer can set up rules. For example: If the name field is blank, take the user back to the form and display an error message.
A feature of HTML whereby the designer can subdivide the page into separate windows. Frames can improve navigation in certain instances, but the drawbacks are significant and numerous. Most notably, framed pages cannot be bookmarked, some browsers cannot display frames at all and search engines might have a hard time indexing framed content.
In programming, a function is a section of code that can be invoked from other sections of the code or from other pages. The main benefit is that code that would otherwise be repeated often in a site can be placed in a function and invoked when needed. This makes for neater code and easier maintenance.
In PHP, many pre-defined functions exist. See PHP.net for a complete list.