rd may refer to:
- an artist who signed one or more artworks with the text "RD"
- something else[1]
Details about the text "rd" 
Edit
The text "rd" is used in a Google GET parameter named "gws_rd". "gws" is an initialism of "Google web server", and "rd" is short for "redirect". If the argument being passed to the gws_rd parameter is "ssl", as in "https://images.google.com/?gws_rd=ssl", then it means that Google is redirecting to a Secure Sockets Layer version of itself.[2]
