If you first understand the word "or", then you will also understand the word "either". So let's start by explaining "or". When you say "A is true OR B is true", it means that one of these three possibilities is true: 1. A is true and B is false. 2. A is false and B is true. 3. A is true and B is true. The statement "A (is true or B (is true)" does not tell you which of the three outcomes is correct. It is up to you to decide, or not decide, based on whatever information is available to you, and also upon whether or not you care. "Either" works exactly the same way. It does not give you the information to answer your question. It is intentionally ambiguous. So if Sally says to you "You may eat either the red cookie or the blue cookie", it is not clear whether you are allowed to eat both. However, by listening to how Sally says it, you may be able to infer that she doesn't want you to eat both. For example, if she SHOUTS at you the word "OR", saying "You may eat either the red cookie OR the blue cookie" then you may infer that she doesn't want you to eat both. However, to be certain you must ask her "Can I eat both?"

I would say it depends on the nature of the verb, whether it is affirmative or negative, etc. 'I don't like either choice.' The main point here is 'I don't like,' so then, both choices I don't like. 'You can choose either option.' The main point here is that you can choose. So then, you can choose from both options / from one or the other option. 'I can't tell one from the other.' The main point is 'I can't tell/distinguish. Then, both things are very similar or indistinguishable from each other.

The word "either" can indeed have two different meanings depending on the context, and it can be used to refer to "both" or "one or the other." The meaning is typically determined by the surrounding words and the structure of the sentence. Here's how to distinguish between the two meanings: "Either" meaning "Both": When "either" is used to mean "both," it is often followed by "and." For example: "You can have either chocolate and vanilla ice cream." In this context, it means you can have both chocolate and vanilla flavors. "Either" meaning "One or the Other": When "either" is used to mean "one or the other," it is often followed by "or." For example: "You can choose either chocolate or vanilla ice cream." In this context, it means you can choose either the chocolate flavor or the vanilla flavor but not both. In summary, the distinction between "either" meaning "both" and "either" meaning "one or the other" is primarily determined by whether it is followed by "and" (both) or "or" (one or the other) in the sentence. Paying attention to the conjunction used can help clarify the intended meaning.