THESAURUS
buffer state
ally, archduchy, archdukedom, barrier, body politic, brattice, buffer, bulkhead, bumper, captive nation, chieftaincy, chieftainry, city-state, cloison, collision mat, colony, commonweal, commonwealth, country, county, cushion, diaphragm, dissepiment, dividing line, dividing wall, division, domain, dominion, duchy, dukedom, earldom, empery, empire, fender, free city, grand duchy, interseptum, kingdom, land, mandant, mandate, mandated territory, mandatee, mandatory, mat, midriff, midsection, nation, nationality, pad, panel, paries, partition, party wall, polis, polity, possession, power, principality, principate, property line, protectorate, province, puppet government, puppet regime, realm, republic, satellite, seneschalty, separation, septulum, septum, settlement, shock pad, sovereign nation, state, sultanate, superpower, territory, toparchia, toparchy, wall