Smithsonian rhymes with:
jacksonian, jeffersonian, usoniam, amazonian, andonian, apollonian, babylonian, bostonian, caledonian, devonian, draconian, estonian, gorgonian, houstonian, jacksonian, jeffersonian, melkonian, newtonian, oregonian, patagonian, plutonian, simonian, usoniam, washingtonian
Smithsonian sounds like:
semitism, smidgen, smithson, somatogen, soundscan, swendsen