What is the origin of the word ‘Bar’?

The origin of the word ‘Bar’ is although dating back many years and associated with England for centuries is actually believed to come from an old French word ‘Barra rod’ or ‘Barre’, meaning barrier or rod, which is believed to come about as a result of the barrier separating those drinking from those serving the drinks. 

It is believed to have entered the English language at around 1200 AD.  The word 'tavern' is much older whcih is derived from the Latin 'taberna' whose original meaning was a shed, workshop, or pub. Over time, the words 'tavern' and 'inn' became interchangeable and  in England, inns started to be referred to as public houses or pubs and the term became standard for all drinking house.