The HTML <article> element represents a self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable (e.g., in syndication). This could be a forum post, a magazine or newspaper article, a blog entry, an object, or any other independent item of content. Each <article> should be identified, typically by including a heading (<h1>-<h6> element) as a child of the <article> element.
The HTML <aside> element represents a section of the page with content connected tangentially to the rest, which could be considered separate from that content. These sections are often represented as sidebars or inserts. They often contain the definitions on the sidebars, such as definitions from the glossary; there may also be other types of information, such as related advertisements; the biography of the author; web applications; profile information or related links on the blog.
The HTML <base> element specifies the base URL to use for all relative URLs contained within a document. There can be only one <base> element in a document.
The HTML basefont element (<basefont>) establishes a default font size for a document. Font size then can be varied relative to the base font size using the <font> element.
The HTML Big Element (<big>) makes the text font size one size bigger (for example, from small to medium, or from large to x-large) up to the browser's maximum font size.
The HTML <blockquote> Element (or HTML Block Quotation Element) indicates that the enclosed text is an extended quotation. Usually, this is rendered visually by indentation (see Notes for how to change it). A URL for the source of the quotation may be given using the cite attribute, while a text representation of the source can be given using the <cite> element.
The HTML Center Element (<center>) is a block-level element that can contain paragraphs and other block-level and inline elements. The entire content of this element is centered horizontally within its containing element (typically, the <body>).
The HTML <dd> element (HTML Description Element) indicates the description of a term in a description list (<dl>) element. This element can occur only as a child element of a description list and it must follow a <dt> element.
The HTML Deleted Text Element (<del>) represents a range of text that has been deleted from a document. This element is often (but need not be) rendered with strike-through text.
The HTML <dl> element (or HTMLDescription List Element) encloses a list of pairs of terms and descriptions. Common uses for this element are to implement a glossary or to display metadata (a list of key-value pairs).
<frame> is an HTML element which defines a particular area in which another HTML document can be displayed. A frame should be used within a <frameset>.
Heading elements implement six levels of document headings, <h1> is the most important and <h6> is the least. A heading element briefly describes the topic of the section it introduces. Heading information may be used by user agents, for example, to construct a table of contents for a document automatically.