まっ四角[masshikaku] square
一天四海[ittenshikai] the world
下四半期[shimoshihanki] last quarter (of the year)
弦楽四重奏曲[gengakushijuusoukyoku] string quartet
再三再四[saisansaishi] repeatedly

三寒四温[sankanshion] alternation of three cold and four warm days
四つ[yottsu] four
四つんばい[yotsunbai] (crawl) on all fours
四つ角[yotsukado] four corners
四つ足[yotsuashi] four-footed (animal)

タイ国[taikoku] Thailand
ドイツ民主共和国[doitsuminshukyouwakoku] German Democratic Republic (i.e. former East Germany)
ドイツ連邦共和国[doitsurenpoukyouwakoku] Federal Republic of Germany (former West Germany)
亜米利加合衆国[amerikagasshuukoku] United States of America
愛国[aikoku] love of (one's) country

愛国者[aikokusha] patriot
愛国主義[aikokushugi] nationalism
愛国心[aikokushin] patriotic feelings
夷国[ikoku] land of the barbarians
異国[ikoku] foreign country