411 REFERENCE · Wikibooks
HyperText Markup Language/Tag List/center
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
The tag was used to contain both block-level and inline elements on a web page. Anything contained in the tags would be aligned with the middle of the page.
However it's now obsolete since HTML5, and has been replaced by the CSS property text-align:center.