Descriptive information in a dictionary entry, etc.
Entries should have at least one separate definitions.
description is then used for most of the other information, including
examples. The class attribute has an uncontrolled vocabulary and
can be used to clarify the purposes of the description
elements.
From IUPAC Dictionary of Medicinal Chemistry
<entry id="a7" term="Allosteric enzyme">
<definition>An <a href="#e3">enzyme</a>
that contains a region to which small, regulatory molecules
("effectors") may bind in addition to and separate from the
substrate binding site and thereby affect the catalytic
activity.
</definition>
<description>On binding the effector, the catalytic activity of the
<strong>enzyme</strong> towards the substrate may be enhanced, in
which case the effector is an activator, or reduced, in which case
it is a de-activator or inhibitor.
</description>
</entry>