or

(ôr; ər when unstressed)

1. a. Used to indicate an alternative, usually only before the last term of a series: hot or cold; this, that, or the other.
   b. Used to indicate the second of two alternatives, the first being preceded by either or whether: Your answer is either ingenious or wrong. I didn't know whether to laugh or cry.
   c. Archaic Used to indicate the first of two alternatives, with the force of either or whether.
2. Used to indicate a synonymous or equivalent expression: acrophobia, or fear of great heights.
3. Used to indicate uncertainty or indefiniteness: two or three.

(ôr) Archaic

(ôr)

(ôr)

1. operating room
2. operations research
3. Oregon
4. owner's risk