Haplography
Haplography (from Greek: haplo- 'single' + -graphy 'writing') is the act of writing once what should be written twice. For example, the English word idolatry, the worship of idols, comes from the Greek eidololatreia, but one syllable has been lost through haplography. Other examples are "endontics" for "endodontics", and "voraphilia" for "vorarephilia".