A fork of Rural Dictionary
Someone who has a lot of the same interests and similar personality type. If you two were to bang it would be a cosmic event. You and your cosmic twin would be a great couple if you ever got together even though this would probably happen when you two are in your late 60s-early 70s
Gimli: "Yo, Aragorn and Arwen look so cute together!"
Legolas: " I know! They have so much in common too! They must be Cosmic Twins!"