Kudo vs. Kudos You’ve probably heard these words floating around various celebrations, but do you know the difference? Kudos is a noun that means “praise, honor, or acclaim.” Kudo is the singular version of kudos, but kudos is also singular. Kudos comes from the Greek word kydos, which means praise or renown. Kudos are usually offered in response to an exceptional achievement. A Brief History of Kudos The word kudos first appeared in English-speaking contexts in the 1800s. By the 1920s, it began to appear as a plural noun. The -s ending in English gives the impression that kudos is plural, but in Greek, it’s singular. The word kudo began to appear some time around the mid 1940s.. In 1950, comedian Fred Allen wrote a letter to Groucho Marx where Allen told a story about a lively discussion he overheard at a deli. He described how a patron “interjected a kudo” into the discussion. Back Formation of Kudo Kudo is a back formation from kudos. Back formation is the creation of a new word based on a misinterpretation of an existing word. A back formation can involve removing a supposed or an actual affix (an extra element added to the beginning or end of a word to modify its meaning). In English, -s is an affix that usually makes words plural. So the singular form of kudos mistakenly became kudo. When to Use Kudo or Kudos There aren’t a lot of hard and fast rules about when to use kudo versus kudos any more. Kudos is still the preferred choice for use in formal English. Kudo or kudos can both be used with singular verbs. Not all grammar experts agree that kudo is a word. Nevertheless, the word appears often in entertainment journalism, which tends to favor a more colloquial, on-trend voice. Kudo was used in the title of an article from a 2014 edition of Variety: “D.P. John Bailey to be Honored With ASC’s Highest Career Kudo.” A 2006 article in Backstage magazine refers to the Nickelodeon Kids’ Choice Awards as a “kudo-fest.” Congratulations to you for expanding your vocabulary! Don't Get Mixed Up Again! Get Dictionary.com tips to keep words straight ... right in your inbox. Email address* Valid email addressNameThis field is for validation purposes and should be left unchanged.