Fission rhymes with:
abolition, academician, acquisition, addition, admission, admonition, ambition, ammunition, apparition, attrition, audition, britian, clinician, coalition, cognition, commission, competition, composition, condition, contrition, daffynition, decommission, decomposition, definition, demolition, dentition, deposition, dietician, dietitian, dimunition, disposition, edition, electrician, emission, erudition, exhibition, expedition, exposition, extradition, fondkommission, fruition, geriatrician, ignition, imposition, inhibition, inquisition, intermission, intuition, juxtaposition, logician, magician, malnutrition, mathematician, mccuistion, misrecognition, mission, mortician, munition, musician, nutrition, obstetrician, omission, opposition, optician, partition, patrician, pediatrician, permission, petition, physician, politician, position, precondition, predisposition, preignition, premonition, presupposition, prohibition, proposition, recission, recognition, recondition, redefinition, redeposition, reimposition, remission, rendition, repetition, reposition, requisition, retransmission, rhetorician, sedition, statistician, submission, superstition, supposition, suspicion, tactician, technician, theoretician, titian, tradition, transition, transmission, tuition, volition, wishon
Fission sounds like:
facchini, faciane, fagan, fagen, fagin, faison, fasano, fasciano, fascism, fashion, fason, fasone, faughn, faughnan, faxon, fazzino, feagan, feagin, fegan, feigen, feighan, feigin, feign, ficken, ficom, figone, fijian, fischman, fishkin, fishman, fossen, fossum, foxman, fujian, fujiyama, fukushima, fukuyama, fusion, fuson