Can "either" mean both "any" and "both"

I was checking out the definition of either in dictionary, here is what I found:

one or the other of two things (any of the things will be fine)

one and the other of two things (either side of the road)

so, the word "either" can basically mean both any or both, is that right?

Let's say I want to say:

Either of these options will do (any of the two options will do)

Can it also mean both of the options will do?

Solution 1:

Yes, that’s right. In general, it turns out that sometimes either is distributive, essentially meaning both or all, and sometimes it is exclusionary and so applies to just one out of the set.

Your question is whether it would be understood to mean just one or if it would mean two in the sentence:

Either of these options will do.

The answer is that here it means that just one option suffices. It means “any single option”. If you have any doubts about how it will be received, you can always write any one option or some such.

For the most part, I think the “each one” or “both” sense applies to natural pairs. Here are some OED citations for the “both” kind of either:

• 1762 Falconer Shipwr. Proem 40 ― The fierce extremes of either zone.
• 1820 Scott Ivanhoe iii, ― There was a huge fireplace at either end of the hall.
• 1842 Tennyson E. Morris 37 ― Either twilight and the day between.

Note that either meaning “both” is the oldest of the various senses the word has come to mean historically. It is somewhat uncommon these days, but by no means wholly obsolete.

Solution 2:

"Either" and "Both" have strikingly similar definitions (in at least one of their definitions):

either : being the one and the other of two

both : the one as well as the other

However, "both" often has a context of at the same time, whereas "either" often has a context of one at a time. So there are certainly times when they are not interchangeable. For instance:

I'd like either an apple or an orange.

I'd like both an apple and an orange.

But there are also times where they are interchangeable:

Bob plays both instruments well.

Bob plays either instrument well.

It all depends on context.