It is thought that the method of serving from a bar counter was invented by Isambard Kingdom Brunel, the great Victorian engineer, as a means of more quickly serving the sudden rush of customers caused by passenger trains arriving at the terminus of the Great Western Railway. Before then, the only method known was to wait at tables. If this is true, then the first bar would have been installed at the Great Western Hotel on Paddington Station, London.  Prior to serving alcoholic beverages at a bar counter, gathering in a tavern to drink beer or other alcoholic drinks has been a longstanding social tradition dating at least to Sumer (3500 BC). 

In the United States, a bar is a business that sells alcoholic beverages for immediate on-premises consumption. Contrary to popular belief, there is no discernible difference between bars, pubs, and taverns.  However, the term "bar" outside of the U.S. may specifically connotate different types of establishments. 

In the UK and Ireland, "bars" are either areas that serve alcoholic drinks within establishments such as hotels, restaurants, universities, or are a particular type of establishment which serves specific alcoholic drinks such as "wine bars". However the main type of establishment selling alcohol for consumption on the premises is the public house or "pub".

In Australia, traditionally the "public bar" was where only men drank, while the "lounge bar" or "saloon bar" was where women or men could drink (i.e. mixed drinking).  This distinction is not seen now as anti-discrimination legislation and women's rights activism has broken down the concept of a public drinking area accessible to only one sex.