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

布衍[fuen] expatiation
衍文[enbun] (inadvertent) redundancy in a text

衍字[enji] (inadvertent) insertion of a character in a text