either vs though

either

adv
  • As well. 

pron
  • One or the other of two people or things. 

conj
  • Introduces the first of two (or occasionally more) options or possibilities, the second (or last) of which is introduced by “or”. 

det
  • Any one (of two). 

  • Each of two; both. 

though

adv
  • Despite that; however. 

  • Used to intensify statements or questions; indeed. 

conj
  • Despite the fact that; although. 

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