Just as with Bootstrap 3, Bootstrap 4 styles HTML's built-in abbr tag, which gives developers the ability to denote abbreviations. Denoting a piece of text as being an abbreviation will result in a small, dotted line being drawn underneath the text. As the user hovers over the text, the mouse pointer will change into a question mark. By setting the title attribute, a tool top will appear with the full title attribute's text content:

    <abbr >ABBR</abbr>

And, just as with Bootstrap 3, the initialise class can be used in conjunction with the abbr tag in order to reduce the font size.