Beer garden and Pub

Beer garden noun - Tavern with an outdoor area (usually resembling a garden) where beer and other alcoholic drinks are served.

Pub and beer garden are semantically related in tavern topic. In some cases you can use "Pub" instead a noun phrase "Beer garden", when it comes to topics like barroom, beer hall, establishment serving alcohol.

Pub noun - A place of business where alcoholic beverages are sold to be consumed on the premises.

Beer garden and pub are semantically related in beer hall topic. You can use "Beer garden" instead a noun "Pub".