Source : Webster's Revised Unabridged Dictionary (1913)

Dissimilation \Dis*sim`i*la"tion\, n.
   The act of making dissimilar. --H. Sweet.

Source : WordNet®

dissimilation
     n 1: a linguistic process by which one of two similar sounds in a
          word becomes less like the other; "the Old French MARBRE
          became the English MARBLE by dissimilation"
     2: breakdown of more complex substances into simpler ones with
        release of energy [syn: {catabolism}, {katabolism}, {destructive
        metabolism}] [ant: {anabolism}]