This is a strange blunder. A napperon , converted into An apperon. “Napperon” is French for a napkin, from nappe (cloth in general). Halliwell, in his Archaic Dictionary, p. 571, gives Nappern (an apron) North.
Other examples of n attached to the following noun, or detached from it, are an adder for a nadder (Old English, noeddre); a newt for an ewt; a nag (Danish, ög ); nuncle (Shakespeare), mine uncle; For the nonce (this once), where n is transferred from the preceding pronoun tha-n or the-n, i.e. this-n (accusative case after “for”).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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