English Experts

[Adriano Japan]

a shop, or a counter in a pub or hotel, where alcoholic drinks are sold for consumption elsewhere US equivalents package store liquor store.

An off licence is a British store that sells alcohol by the bottle to be drank outside of the shop.
On licenses are stores on which you can buy drinks and take them either on or off the premises (pubs, restaurants etc).

Off licences are those which you can buy drinks but they have to be consumed only off the premises (supermarkets, corner shops etc) hence the term "off license".

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