HTML
HTML ABBREVIATION & DEFINITION
1) ABBREVIATION
<p> An <abbr title="Extraterrestrial"> ET</abbr> has been reportedly thrown out of a <abbr title="Unknown Flying Object">UFO</abbr>. </p>
DEFINES AN ABBREVATION & FULL TERM
2) DEFINITION
<p> <dfn>Humans</dfn> are bipedal creatures that walk the surface of Earth. Otherwise known as homo sapiens. </p>
DENOTES THE SUBJECT
3) ABBR & DFN
<p> <dfn><abbr title="Model View Controller">MVC </abbr></dfn> is a software design pattern commonly used for developing user interfaces which divides the related program logic into three interconnected elements. - Wikipedia </p>
WHEN AN ABBREVIATION IS ALSO THE SUBJECT