Board Thread:Editor Board/@comment-26391060-20131012140629/@comment-26391060-20131012152825

@Gsimenas

From wikipedia:

Ruby characters  (ルビ? )  are small, annotative  glosses that can be placed above or to the right of a  Chinese character when writing languages with logographic characters such as  Chinese or  Japanese to show the pronunciation. Typically called just  ruby or  rubi, such annotations are used as pronunciation guides for characters that are likely to be unfamiliar to the reader.

and, history:

In British typography,   ruby  <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">was originally the <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  name for type<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">with a height of 5.5 points, which printers used for interlinear annotations in printed documents. In Japanese, rather than referring to a font size, the word became the name for typeset <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  furigana<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">. When transliterated back into English, some texts rendered the word as <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  rubi<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">, (a typical <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  romanization<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">of the Japanese word <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  <span lang="ja" style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">ルビ <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">). However, the spelling "ruby" has become more common since the <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  W3C<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">published a recommendation for <span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">  ruby markup<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">. In the US, the font size had been called " agate<span style="color:rgb(0,0,0);font-family:sans-serif;line-height:19.1875px;">", at least before the 1950s: <p style="line-height:1.5em;">agate: An old name for a size of type slightly smaller than five and one-half points, …. Called ruby in England.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:1.5em;text-align:right;">— Marjorie E. Skillin, et al., Words into Type, 1948, p. 538