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)

満更夢ではない[manzarayumedehanai] not altogether a dream
一更[ikkou] first watch
五更[gokou] the five night watches
更かす[fukasu] to sit up late
更ける[fukeru] to get late

更なり[saranari] of course
更に[sarani] furthermore
更位[koui] second accession of the same emperor
更衣室[kouishitsu] locker room
更改[koukai] renewal