A number of words in English are more commonly found in their classical plural form than in their classical singular form. Because of this dominant usage of the plural form, many people remain unaware that each of the words is already a plural and they treat them as if they were singular forms. For example, the word APOCRYPHA (writings of doubtful authorship) is the plural of APOCRYPHON. But as APOCRYPHA is often regarded as the singular, the erroneous plural APOCRYPHAS is sometimes encountered.
Word Ways: Vol. 4
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol4/iss3/15