There are several synonyms for the word "superhorizon" which refer to objects or events beyond the reach of a viewer's horizon. These include "transhorizon," "ultrahorizon," and "extrahorizon." All of these terms suggest something that lies beyond what is currently visible but may become visible in the future. These words are often used in astronomy and space exploration to describe objects that are believed to exist beyond the observable universe, or events that occurred before the universe was visible. Overall, these synonyms for "superhorizon" offer a sense of mystery and intrigue about what lies beyond our current understanding and observation of the world around us.