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)

アナログ計算機[anarogukeisanki] analog computer
コンピューター援用設計[konpyuutaaenyousekkei] computer-aided design
圧力計[atsuryokukei] manometer
移行計画[ikoukeikaku] transition plan
一計[ikkei] plan

一般会計[ippankaikei] general accounting and finance
雨量計[uryoukei] rain gauge
温度計[ondokei] thermometer
家計[kakei] household economy
家計簿[kakeibo] household account book