 Homers trademark was the expressive "Doh!". After a few seasons,  that particular word was finally considered valid, accepted and  finally appeared in the online version of The Oxford Dictionary.  According to actor Dan Castellaneta (qv), the word means "annoyed  grunt" as it was written in the script. He came out with the word  "Dooooh..." from Stan Laurel (qv) and Oliver Hardy (qv) and made  it quicker for animation.