The last time we discussed how to rank in Google Definitions was about two-plus years ago. Although Google has consistently removed the traffic value for third-party sites with Google Definitions, it still can drive some traffic to your site.
A new WebmasterWorld thread has revived interest around getting included in Google Definitions. In that thread, WebmasterWorld administrator says he has had success using the DL and DT tag/elements.
You can learn more about how to use those elements in your HTML at w3.org. Here is a sample of HTML:
<dl>START DEFINITION LIST
<dt>FIRST TERM TO BE DEFINED GOES HERE</dt>
<dd>DEFINITION OF FIRST TERM GOES HERE</dd>
<dt>SECOND TERM TO BE DEFINED GOES HERE</dt>
<dd>DEFINITION OF SECOND TERM GOES HERE</dd>
CONTINUE MORE TERMS ...
Anyone have success with that? That was part of our recommendation in 2008.
Forum discussion at WebmasterWorld.