Gives some extra info that isn’t a part of the main content flow. Like a footnote.

This is an aside.

Here’s some code:

.aside {
  font-size: 12px;
  font-style: italic;
  margin-left: 200px;
  text-align: right;
}
...
<p class="aside">This is an aside.</p>

Figure 1. Code for an aside

If the aside is long and runs over more than one line, margin-left: 200px; (line 4) makes sure there is some space on the left. Here’s an example:

This is a very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very long aside.