either vs or

either

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

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

det
  • Any one (of two). 

  • Each of two; both. 

adv
  • As well. 

or

conj
  • Counts the elements before and after as two possibilities. 

  • Connects at least two alternative words, phrases, clauses, sentences, etc., each of which could make a passage true. 

  • Otherwise (a consequence of the condition that the previous is false). 

  • Connects two equivalent names. 

  • An operator denoting the disjunction of two propositions or truth values. There are two forms, the inclusive or and the exclusive or. 

adj
  • Of gold or yellow tincture on a coat of arms. 

prep
  • Before; ere. Followed by "ever" or "ere". 

noun
  • or 

  • The gold or yellow tincture on a coat of arms. 

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