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)

異象[ishou] vision
印象[inshou] impression
印象主義[inshoushugi] impressionism
印象的[inshouteki] impressive
印象派[inshouha] Impressionists

横並び現象[yokonarabigenshou] herd instincts
温暖化現象[ondankagenshou] greenhouse effect
海象[seiuchi] walrus (Odobenus rosmarus)
気象[kishou] weather
気象学[kishougaku] meteorology