» For the chemical term, see catabolism In phonology, particularly within historical linguistics, dissimilation's a phenomenon whereby similar consonant or vowel sounds in a word become less similar. For example, when one /r/ sound occurs before another in the middle of a word in rhotic dialects of English, the first tends to drop out, as in "beserk" for berserk, "supprise" for surprise, "paticular" for particular, and "govenor" for governor (note this doesn't affect the pronunciation of govern… (More on Dissimilation)