Digestion rhymes with:
indigestion, indigestion, congestion, indigestion, ingestion, suggestion, congestion, indigestion, ingestion, question, suggestion
Digestion sounds like:
d'agostino, dagestan, dagostino, dakotan, daughton, dedication, deduction, degaetano, deighton, desiccation, destin, destiny, destitution, detection, detoxication, dichotomy, dickstein, dictation, diction, dictum, dideoxycytidine, digaetano, digidyne, disdain, dissection, dissociation, doughten, dukedom, dustin, dustman, duston