Fortress rhymes with:
actress, ambidextrous, beatrice, buttress, citrus, dextrous, disastrous, estrous, estrus, headmistress, idolatrous, kontras, lustrous, mattress, mistress, monstrous, nitrous, peatross, petrus, sentras, waitress, watrous
Fortress sounds like:
fortier's, fortresses, forwarders, frederic, frederica, frederick, frederick's, fredericka, fredericks, frederico, frederika, fredric, fredrich, fredrick, fredricks, fridrich, friederich, friederike, friedrich, friedrichs, friedrick, furthers