bootstrap4.css
abbr[title],
abbr[data-original-title] {
  text-decoration: underline;
  -webkit-text-decoration: underline dotted;
  text-decoration: underline dotted;
  cursor: help;
  border-bottom: 0;
  -webkit-text-decoration-skip-ink: none;
  text-decoration-skip-ink: none;
}
bootstrap4.css
@media print {
  *,
  *::before,
  *::after {
    text-shadow: none !important;
    box-shadow: none !important;
  }
  a:not(.btn) {
    text-decoration: underline;
  }
  abbr[title]::after {
    content: " (" attr(title) ")";
  }
  pre {
    white-space: pre-wrap !important;
  }
  pre,
  blockquote {
    border: 1px solid #adb5bd;
    page-break-inside: avoid;
  }
  thead {
    display: table-header-group;
  }
  tr,
  img {
    page-break-inside: avoid;
  }
  p,
  h2,
  h3 {
    orphans: 3;
    widows: 3;
  }
  h2,
  h3 {
    page-break-after: avoid;
  }
  @page {
    size: a3;
  }
  body {
    min-width: 992px !important;
  }
  .container {
    min-width: 992px !important;
  }
  .navbar {
    display: none;
  }
  .badge {
    border: 1px solid #000;
  }
  .table {
    border-collapse: co
■テキスト:Text:ユーティリティ:略語 abbr要素

HTML

HTML

  <p><abbr title="HyperText Markup Language">HTML</abbr></p>
  <p><abbr title="HyperText Markup Language" class="initialism">HTML</abbr></p>