Originariamente inviato da pierofix
Ecco il w3c cosa dice in merito (fonte: specifica di html 4.0).

Definition lists vary only slightly from other types of lists in that list items consist of two parts: a term and a description. The term is given by the DT element and is restricted to inline content. The description is given with a DD element that contains block-level content.

Here is an example:
codice:
<DL>
  <DT>Dweeb
  <DD>young excitable person who may mature
    into a Nerd or Geek

  <DT>Hacker
  <DD>a clever programmer

  <DT>Nerd
  <DD>technically bright but socially inept person

</DL>
Here is an example with multiple terms and descriptions:
codice:
<DL>
   <DT>Center
   <DT>Centre
   <DD> A point equidistant from all points
              on the surface of a sphere.
   <DD> In some field sports, the player who
              holds the middle position on the field, court,
              or forward line.
</DL>
Another application of DL, for example, is for marking up dialogues, with each DT naming a speaker, and each DD containing his or her words.

---

Applicandole alle barre di navigazione, è come assegnare ad una lista di link una determinata definizione.

:master: rimango del mio parere, meglio i titoli, secondo me gli elementi di un sottomenu non sono definizioni del nome di quel sottomenu, ma il titolo sottomenu serve solo a descrivere gli elementi della lista ... guarda quanti header correlati a ul nell'home del w3c:
codice:
<h2 class="navhead"><a name="contents" id="contents" shape="rect">Members</a></h2>

<div class="hpmt"><div class="hpmt-name">SICS</div><div class="hpmt-logo"></div><p class="hpmt-testimonial">SICS (Swedish Institute of Computer Science) promotes the uptake of Web standards through advanced IT research and development in collaboration with national and international industry, as well as with public sector organizations. SICS is also hosting the Swedish W3C Office.
 (Member testimonials)</p></div>

<ul>[*]Member Home Page
[*]Member Submissions
[*]<a href="/Consortium/Member/List" class="navlink" shape="rect">Current
Members</a>
[*]<a href="/Consortium/Recruitment/Fellows" class="navlink" shape="rect">W3C
Fellows</a>[/list]

<h2 class="navhead">Get Involved</h2>

<ul>[*]<a href="/Consortium/Prospectus/" class="navlink" shape="rect">W3C Membership
Benefits</a> (Apply)
[*]Mailing Lists
[*]Translations
[*]<a href="/Consortium/Offices/" class="navlink" shape="rect">World
Offices</a>
[*]Workshops
[*]W3C Donors
[*]Open Source Software
[*]Employment
[*]More ways to participate[/list]

<h2 class="navhead">Introduction</h2>

<ul>[*]<a href="/Consortium/Points/" class="navlink" shape="rect">W3C in Seven
Points</a>
[*]<a href="/Consortium/W3C-FAQs" class="navlink" shape="rect">Frequently Asked
Questions (FAQ)</a>
[*]Tutorials
[*]<a href="/Consortium/Process/" class="navlink" shape="rect">Process
Document</a>
[*]More...[/list]

<h2 class="navhead">W3C Team</h2>

<ul>[*]People
[*]<a href="/TeamSubmission/" class="navlink" shape="rect">Team
Submissions</a>[/list]