The HTML <ruby> tag specifies ruby annotations, which are for East Asian characters’ pronunciation. You can try to run the following code to display ruby annotation −
Example
<!DOCTYPE html> <html> <head> <title>HTML Ruby Tag</title> </head> <body> <ruby> 明日 <rp>(</rp><rt>This is it</rt><rp>)</rp> </ruby> </body> </html>