The **`<abbr>`** [HTML](https://developer.mozilla.org/en-US/docs/Web/HTML) element represents an abbreviation or acronym.
When including an abbreviation or acronym, provide a full expansion of the term in plain text on first use, along with the `<abbr>` to mark up the abbreviation. This informs the user what the abbreviation or acronym means.
The optional [`title`](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes#title) attribute can provide an expansion for the abbreviation or acronym when a full expansion is not present. This provides a hint to user agents on how to announce/display the content while informing all users what the abbreviation means. If present, `title` must contain this full description and nothing else.