HTML <rt> Tag

 <rtc>San Francisco

The above example demonstrates usage of the <rt> element.

The <rt> element marks the ruby text component of a ruby annotation.

The above example was borrowed from the W3C example. In this example, a base is annotated twice. The Chinese word for San Francisco (旧金山, i.e. "old gold mountain") is annotated both using pinyin to give the pronunciation, and with the original English.

About Ruby

Ruby (also spelt rubi) characters are small, annotative glosses that can be placed above or to the right of a Chinese character when writing logographic languages such as Chinese or Japanese to show the pronunciation. Ruby annotations, are usually used as a pronunciation guide for relatively obscure characters.