(nonstandard, humorous, science fiction) Of or from the planet Earth.
2002 April 23, Jym Dyer, “Earthican Dayâ€, alt.tv.futurama, UsenetI went to an Earth Day event in San Francisco and there was this huge Earthican flag, circa 3000 A.D., with the red and white stripes and an image of Earth up in the corner.
2004 October 18, Wayne Throop, “Early parallel-universe stories†rec.arts.sf.written, UsenetJust consider that, over time, on a scale of millions of years, earthican continents have had *lots* of different configurations
2006 May 25, James Nicoll, “Spider's Heinlein novel Re: ConCarolinas 2006 is coming!â€, rec.arts.sf.fandom, UsenetYou may remember him Hellyer from such news articles as "Is there a party Paul hasn't belonged to or at least tried to join?" and "How dare the Americans threaten the delicate Earthican-Alien relationship by planning to emplace armed bases on the Moon?"
2006 June 27, John Schilling, “David Drake - Leary and the RCNâ€, rec.arts.sf.written, Usenetthat first step is enough to make direct attacks rather tricky, to make most of the Earthican powers' armed forces useless.