HTML <dt> Tag with a nested <dfn> Tag

<dd>A tool with a heavy metal head mounted at right angles at the end of a handle, used for jobs such as breaking things and driving in nails.</dd>
<dd>A tool for cutting wood or other materials, typically with a long, thin serrated steel blade and operated using a backward and forward movement.</dd>
<dt><dfn>Screw Driver</dfn></dt>
<dd>A tool with a flattened, cross-shaped, or star-shaped tip that fits into the head of a screw to turn it.</dd>

The above example demonstrates usage of the <dt> element with a <dfn> element nested inside of it.

We do this because we are defining a term and the <dfn> element is used for the defining instance of a term.

About the <dt> Element

The <dt> element represents the term, or name, part of a term-description group in a description list.

You can have multiple <dt> elements for each <dd> element.

You can also have multiple <dd> elements for each term too (if the same term matches multiple descriptions).