Either/both

[Leong187]

a) He sat in the back of the car with a policeman on either side/each side/both sides.
b) There are shops at either end/each end/both ends of the street.

Can we use 'either side', 'each side' and 'both sides' interchangeably in the example sentences above?

Thanks.

[Dozy]

(a) "either side" and "each side" are both OK. "both sides" might pass, but it is not such a good fit with "a policeman". You could say "with policemen on both sides", but then it's ambiguous as to how many on each side.

(b) These are all OK.

[Leong187]

So is it correct to say that 'either' means 'each' and 'both' in this context? Or is there any difference in usage?

Thanks Dozy.

[Dozy]

In sentences like the ones you posted, there is no difference in meaning between "either", "each" and "both". The only difference in usage concerns the issue of plural vs. singular nouns.