Does “or” mean both conditions?

Question

We are ordinary Russian folks playing an English board game and came across this sentence:

You may splay your green or blue cards left.

We expected that it meant you must choose only one card stack, but later found another card with the appended sentence:

Draw a card for every color you have splayed left.

which contradicts the first sentence if "forcing" was intended because it has the words "for every" (not one).

Does "or" mean choosing only one clause in English or does it allow to choose both?

Answer 1

In general, "or" is somewhat ambiguous between whether it does or does not include both. In this particular construction---"You may do X or Y"---the tendency is to mean the exclusive or---one or the other, but not both. (But this isn't entirely clear; as these are supposed to be rules for a game, it would probably help to be clearer.)

The rule is unambiguously permissive: it says you may splay them, but doesn't force you do. (If it intended to say that you had to splay exactly one color, a typical phrasing would have been "You must splay either your green or blue cards left.")

It appears you're discussing the game Innovation. (It would, by the way, have been helpful to include that information in the first place.) In that context, I don't know why you think there's any conflict between the two cards. There are lots of cards that cause you to splay different colors; the card you mentioned splays one color, and other cards may splay other colors, and then a later card counts how many colors you've splayed.

From what I remember of the game, I believe in this case the rule is exclusive---color or the other. But you'd be better off checking on forums associated to board games, or that specific game.

Answer 2

The meaning of "or" is ambiguous and depends on the context in which it is being used.

I can say, however, that in mathematical writing "or" always means "one or the other" or "both".

This meaning is immediately clarified when one first starts learning the basic building blocks of mathematics: set theory.

Answer 3

English is ambiguous when it comes to the use of "or." "Either/or" (for example, "Either take your turn or quit the game") implies one or the other but not both, but "or" by itself can mean either exclusive or non-exclusive. In this case it seems clear that it is not exclusive: use blue, or green, or both.