definition list; definition term; definition description.
In HTML 4,
<dl> was considered a “definition list”, containing groups of terms and their definitions. The terms and definitions were a many-to-many relationship: one or more terms to one or more definitions.
In HTML5, The dl element represents an association list consisting of zero or more name-value groups (a description list). Each group must consist of one or more names (dt elements) followed by one or more values (dd elements). Within a single dl element, there should not be more than one dt element for each name.
It maintains the many-to-many relationship between names and values. These groupings use
<dt> to represent the term or name and
<dd> for the description. Also note the last line of the quote, stating that a name should not be used more than once within a single
<dl> can be used to mark-up a glossary of terms, although you must remember to use
<dfn> to indicate that the word is defined here:
<h2>Glossary</h2> <dl> <dt><dfn>RSS</dfn></dt> <dd>An XML format for aggregating information from websites whose content is frequently updated.</dd> <dt><dfn>Weblog</dfn></dt> <dd>Contraction of the term "web log", a weblog is a website that is periodically updated, like a journal</dd> </dl>