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

し難い[shinikui] hard to do
一難[ichinan] one difficulty
火難[kanan] fire calamity
海難[kainan] shipwreck
患難[kannan] affliction

危難[kinan] peril
及び難い[oyobigatai] hard to attain to
救難[kyuunan] rescue
救難ヘリコプター[kyuunanherikoputaa] rescue helicopter
苦難[kunan] suffering