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)

安全第一[anzendaiichi] safety first
及第[kyuudai] passing an examination
及第者[kyuudaisha] successful examinee
及第点[kyuudaiten] passing mark
次第[shidai] dependent upon

次第に[shidaini] gradually (progress into a state)
次第書き[shidaigaki] printed program
式次第[shikishidai] program of a ceremony (programme)
手当たり次第[teatarishidai] using anything one can lay one's hands on
出来次第[dekishidai] as soon as completed

胃液[ieki] gastric juice
胃炎[ien] gastritis
胃下垂[ikasui] gastroptosis
胃癌[igan] stomach cancer
胃鏡[ikyou] gastroscope

胃散[isan] stomach medicine
胃酸[isan] stomach acid
胃弱[ijaku] dyspepsia
胃洗浄[isenjou] stomach pumping