
1) Typo
Found on
https://www.crosswordclues.com/clue/dittography

Dittography is the accidental, erroneous act of repeating a letter, word, phrase or combination of letters by a scribe or copyist. == ...
Found on
http://en.wikipedia.org/wiki/Dittography

unintentional repetition of letters in print
Found on
http://phrontistery.info/d.html

(from the article `biblical literature`) ...alike. In early manuscripts OC (for hos, `[he] who`), for example, might easily be mistaken for the traditional abbreviation of God: C (for EOC, ... Dittography, or the inadvertent duplication of one or more letters or words, also occurs, as, for example, in the Dead Sea Scroll text ...
Found on
http://www.britannica.com/eb/a-z/d/58

dittography, dittographic Double writing; the unintentional repetition of a letter or word, or series of letters or words, by a copyist.
Found on
http://www.wordinfo.info/words/index/info/view_unit/2458/4

reduplication of letters or syllables in writing, printing, etc., usually through error. Cf. haplography.
Found on
https://www.infoplease.com/dictionary/dittography
No exact match found.