The HTML abbr> element is used to mark up abbreviations or acronyms such as WWW or HTTP. When you hover over an abbr> element, Bootstrap adds a faint dotted border around the bottom and shows the full text (as long as the content is added to the abbr> title attribute). Add.initialism to.abbr> to get a little reduced font size.
<abbr title = "World Wide Web">WWW</abbr><br>
<abbr title = "Real Simple Syndication" class = "initialism">RSS</abbr>
Ans: WWW
RSS