The definition of either or is an expression used to indicate that there are only two options or that both of two options are acceptable or equivalent.
An example of either or is when you are offered either spaghetti or cereal for dinner and are different between the two so you say "either or" to indicate that both would work.
designating a proposition, situation, etc. limited to only two alternatives
also written either/or
A strictly limited choice or division between only two options.
Of or characterized by a choice or division limited strictly between two options: found ourselves in an either-or situation.
- Describing a situation in which there are only two choices.