{{tag|u}} represents a span of text offset from its surrounding content without conveying any extra emphasis or importance, and for which the conventional typographic presentation is underlining; for example, a span of text in Chinese that is a proper name (a Chinese proper name mark), or span of text that is known to be misspelled.
<code><nowiki><{{tag|u></nowiki></code>|o}} was [[HTML element#Presentational markup|presentational element of HTML]] that was originally used to underline text; this usage was [[deprecated]] in HTML4 in favor of the [[CSS]] style <code>{text-decoration: underline}</code>.<ref name=mozilla>{{cite web |url=https://developer.mozilla.org/en-US/docs/Web/HTML/Element/u |title= <nowiki><<u>>: The Unarticulated Annotation (Underline) element</nowiki> | date = 1 August 2020 |access-date= 9 October 2020 | website= mozilla.org}}</ref> In HTML5, the tag reappeared but its meaning was changed significantly: it now "represents a span of inline text which should be rendered in a way that indicates that it has a non-textual annotation".<ref name=mozilla /> This facility is intended for example to provide a red wavy line underline to flag spelling errors at input time but which are not to be embedded in any stored file (unlike an emphasis mark, which would be).
