Glyphicons

Bootstrap comes with 250+ glyphs that you can use as icons. See the full list here. Here's how to use them:

<span class="glyphicon glyphicon-trash"></span>

Accessibility

Make things more accessible by using aria-hidden="true":

<span class="glyphicon glyphicon-trash" aria-hidden="true"></span>

Buttons

Use a glyph in a button as follows:

<button type="button" class="btn btn-default">
  <span class="glyphicon glyphicon-eye-open"></span> Button text
</button>