What? You've never heard the term? This neologism began to show up in pop culture following the International Astronomical Union's (IAU) reclassification in 2006 of Pluto from the 9th planet in our solar system to merely a dwarf planet. The American Dialect Society chose “plutoed” as the 2006 Word of the Year in honor of this change and defines it as “to demote or devalue someone or something.”