carbon-components/html/tooltip/tooltip--definition.html

Carbon Components is a component library for IBM Cloud

<div class="bx--tooltip--definition">
  <button class="bx--tooltip__trigger" type="button" aria-describedby="definition-tooltip">
    Definition Tooltip
  </button>
  <div id="definition-tooltip" role="tooltip" class="bx--tooltip--definition__bottom">
    <span class="bx--tooltip__caret"></span>
    <p>Brief description of the dotted, underlined word above.</p>
  </div>
</div>