The "n" of "an" has sometimes migrated over time to the noun. Perhaps oversimplifying a bit:
an apron became a napron, which became a napkin.
To the ear, an apron and a napron would sound almost exactly alike.

Another example is the word "eke", but no in the sense with is, today, its almost-exclusive usage (to eke out a living). Using it older sense:
a shortened name = an eke name, which became a nekename, which became a nickname