The <overline> element indicates content that is rendered with a line above it. This element is part of the highlighting domain. Use this element only when a more semantically appropriate element is not available.
Style sheets can be used to format the <overline> element differently, just like any other element can be restyled. Thus, it is not the case that content in <overline> elements will necessarily be rendered with a line above.
See appendix for information about this element in OASIS document type shells.
+ topic/ph hi-d/overline
<p>Overline: <overline><i>x</i></overline> is the average value of<i>x<sub>i</sub></i></p>