an vs via

an

prep
  • In each; to or for each; per. 

article
  • Used before one and words with initial u, eu. 

  • Used before a vowel sound. 

  • Used before all consonants. 

  • Used before /h/ in an unstressed syllable. 

  • Used before /h/ in a stressed syllable. 

noun
  • The first letter of the Georgian alphabet, ა (Mkhedruli), Ⴀ (Asomtavruli) or ⴀ (Nuskhuri). 

num
  • one 

via

prep
  • By (means of); using. 

  • By way of; passing through. 

noun
  • A main road or highway, especially in ancient Rome. (Mainly used in set phrases, below.) 

  • A small hole in a printed circuit board filled with metal which connects two or more layers. 

How often have the words an and via occurred in a corpus of books? (source: Google Ngram Viewer )