Definition of "or"

or¹

/ɔɹ/

conjunction
1. Connects at least two alternative words, phrases, clauses, sentences, etc., each of which could make a passage true.
2. (logic) An operator denoting the disjunction of two propositions or truth values. There are two forms, the inclusive or and the exclusive or.
3. Counts the elements before and after as two possibilities.
4. Otherwise (a consequence of the condition that the previous is false).
  Quotations
  No matter how early I came down, I would find him on the veranda, smoking cigarettes, or otherwise his man would be there with a message to say that his master would shortly join me if I would kindly wait.
  1897 December (indicated as 1898), Winston Churchill, chapter IV, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., page 46
5. Connects two equivalent names.

or²

noun
plural ors
1. (logic, electronics) Alternative form of OR

or³

/oɹ/

noun
countable and uncountable, plural ors
1. (heraldry) The gold or yellow tincture on a coat of arms.
  Quotations
  The metals are gold and silver, these being termed "or" and "argent".
  1909, Arthur Charles Fox-Davies, A Complete Guide to Heraldry
  In engraving, "Or" is expressed by dots.
  1889, Charles Norton Elvin, A Dictionary of Heraldry
adjective
not comparable
1. (heraldry) Of gold or yellow tincture on a coat of arms.

or⁴

adverb
1. (obsolete) Early (on).
2. (obsolete) Earlier, previously.
preposition
1. (now archaic or dialect) Before; ere. Followed by "ever" or "ere".
  Quotations
  Or euer the siluer corde be loosed, or the golden bowle be broken, or the pitcher be broken at the fountaine, or the wheele broken at the cisterne. Then shall the dust returne to the earth as it was: and the spirit shall returne vnto God who gaue it.
  1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], Ecclesiastes 12:6-7
  I looked to heaven, and tried to pray;But or ever a prayer had gusht,A wicked whisper came, and madeMy heart as dry as dust.
  1834, Samuel Taylor Coleridge, The Rime of the Ancient Mariner