Onassis' rhymes with:
onassis, onassis, cassis, kassis, onassis, actinomycosis, airbases, alexis, amniocentesis, anaphylaxis, atherosclerosis, beschloss's, biosys, cassis, cedras's, consis, dedominicis, dimitrius's, duplessis, electrophoresis, elephantiasis, elexis, endometriosis, frances, hammas's, ilalis's, kassis, kocis, kocsis, lexis, lysis, metastasis, microgenesys, molpus's, narcisse, nemesis, neurofibromatosis, nexis, oasis, onassis, onassis's, organogenesis, osmosis, osteoporosis, parenthesis, persis, pertussis, photophoresis, photosynthesis, phototaxis, plessis, praxis, preadolescence, prosthesis, publicis, pyxis, rox's, sepsis, solstices, stephanopoulos's, synopsis, tarses, telesis, telexes, thrombolysis, toufexis, transgresses, tuberculosis, urinalysis, vince's
Onassis' sounds like:
oehmens, ohioans, ohm's, ohms, ohnemus, omaha's, omans, omega, omens, ominous, onassis, onassis's, once, one's, oneness, oneok, ones, ones', onex, onex's, ong, onions, onishi, ons, onus, onyx, ounce, ounces, owen's, owens, owens's, owing, owings, owning, owns