(used to connect words, phrases, or clauses representing alternatives)

books or magazines; to be or not to be.

(used to connect alternative terms for the same thing)

the Hawaiian, or Sandwich, Islands.

(used in correlation)

either or; or or; whether or.

(used to correct or rephrase what was previously said)

His autobiography, or rather memoirs, will soon be ready for publication.

otherwise; or else

Be here on time, or we'll leave without you.

Logic . the connective used in disjunction.

conjunction

alternative , either , else , ere , instead , oppositely , rather , substitute , uncertainty