For some reason, those who initiated the HTML5 work got found of the idea that one should change the name "definition list" to "description list".

As consequence, the spec now says this:

  ]] The dl element represents an association list consisting of zero 
     or more name-value groups (a description list). [[

My primary proposal is to replace "description list" in that parenthesis with "definition list". But I would be OK with adding "definition list", e.g. so that the parenthesis woudl say something like this:

  ]] (a description list — also known as a definition lists) [[

Justification:

* The name "definition list" is the inherited name from HTML4
* The name "definition list" is also predominant everywhere
  dl-lists are used.
* The spec uses the term 'definition' and 'definitions' twice 
  when  describing what DL lists are
* Someone searching for the spec's definition of DL-lists, 
  he or she would be likely to search for "definition list"
  or "definition lists".