Stylised implementation of HTML's <abbr> element for abbreviations and acronyms to show the expanded version on hover. Abbreviations with a title attribute providing additional context on hover.
<abbr>
For expanded text on long hover of an abbreviation, include the title attribute.
An abbreviation of the word attribute is attr.
<acronym>
Acronyms for a slightly smaller font-size to accomodate the capitalisation.
HTML is the best thing since sliced bread.