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)

四隅[yosumi] four corners
南隅[nanguu] southern corner
僻隅[hekiguu] corner
片隅[katasumi] corner
一隅[ichiguu] corner

隅々[sumizumi] nooks
隅に置けない[suminiokenai] witty and knowing
隅から隅まで[sumikarasumimade] every nook and corner
隅木[sumiki] angle (corner) block