dissimilation

In linguistics, this term describes a specific phonological phenomenon where the repetition of similar sounds is avoided to prevent tongue-tying or auditory monotony. It is the direct opposite of assimilation, where sounds become more similar. This process often occurs unconsciously to improve the articulatory ease of a word.

In biological and chemical contexts, the term is used as a technical synonym for catabolism. It refers to the breakdown of complex organic molecules to release energy, serving as the necessary counter-balance to assimilation (anabolism), which builds those molecules up.