The dl element is a part of the dl, dt, dd triumvirate of elements used to create a definition list in a document. The entire list is bracketed by the dl element's tags. Each definition term is denoted by a leading dt element tag, and the definition for the term is denoted by a leading dd element tag. A schematic of a definition list sequence for three items looks like the following:

The entire list must close with an end tag for the encapsulating dl element. Note that the dl element is the container of the entire list, which means that inheritable style sheet rules assigned to the dl element apply to the nested dt and dd elements. Unwanted inheritances can be overridden in the dt and dd elements.

Although the HTML specification forces no particular way of rendering a definition list, Navigator and Internet Explorer are in agreement in left-aligning a dt element and indenting any dd element that follows it. No special font formatting or visual elements are added by the browser, but you are free (if not encouraged) to assign styles as you like. If you want to stack multiple terms and/or definitions, you can place multiple dt and/or dd elements right after each other in the source code.

Because HTML is being geared toward context-sensitive tagging, avoid using definition lists strictly as a formatting trick (to get some indented text). Use style sheets and adjustable margin settings to accomplish formatting.

When set to true (by virtue of its presence in the dl element tag), the compact Boolean attribute instructs the browser to render a related dt and dd pair on the same line if space allows. The criterion for determining this space (as worked out in both Navigator and Internet Explorer) is related to the amount of indentation normally assigned to a dd element (indentation size differs slightly with operating system). With compact turned on, if the dt element is narrower than the indentation space, the dd element is raised from the line below and displayed on the same line as its dt element. Because the width of characters in proportional fonts varies so widely, there is no hard-and-fast rule about the number of characters of a dt element that lets the dd element come on the same line. But this compact styling is intended for dt elements consisting of only a few characters. This attribute is deprecated in HTML 4, and does not validate in strict HTML 4 or XHTML.

The language being used for the element's attribute values and content. A browser can use this information to assist in proper rendering of content with respect to details such as treatment of ligatures (when supported by a particular font or required by a written language), quotation marks, and hyphenation. Other applications and search engines might use this information to aid the selection of spell-checking dictionaries and the creation of indices.