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)

アラビア数字[arabiasuuji] Arabic numeral
キリル文字[kirirumoji] Cyrillic character
ギリシア文字[girishiamoji] Greek character
羅馬字[roomaji] Latin alphabet
ロシア文字[roshiamoji] Russian character

異体字[itaiji] kanji variants
一字[ichiji] letter
一字千金[ichijisenkin] word of great value
一丁字[itteiji] single letter or character
一文字[ichimonji] straight line

熟々[tsukuzuku] completely
円熟[enjuku] ripeness
黄熟[koujuku] ripening and turning yellow
噛熟す[kamikonasu] to chew
完熟[kanjuku] completely ripe or mature

使い熟す[tsukaikonasu] to handle (men)
四字熟語[yojijukugo] four-character idiomatic compounds
修熟[shuujuku] developing skill
習熟[shuujuku] skilled
熟す[jukusu] to ripen

オブジェクト指向言語[obujekutoshikougengo] object-oriented language
コンピュータ用語[konpyuutayougo] computerese
スウェーデン語[suweedengo] Swedish (language)
スペイン語[supeingo] Spanish (language)
スワヒリ語[suwahirigo] Swahili (language)

チャン語[chango] Chinese (language)
ドイツ語[doitsugo] German (language)
フランス語[furansugo] French (language)
プログラム言語[puroguramugengo] programming language
ペルシャ語[perushago] Persian (language)