In Wikipedia, we find this general definition of a public house:
"A public house, is an establishment licensed to serve alcoholic drinks for consumption on the premises. The term public house first appeared in the late 17th century, and was used to differentiate private houses from those which were, quite literally, open to the public as 'alehouses', 'taverns' and 'inns'. By Georgian times it had become common parlance, although taverns, as a distinct establishment, had largely ceased to exist by the beginning of the 19th century. The Campaign for Real Ale states that a pub has four characteristics:
1. is open to the public without membership or residency; 2. serves draught beer or cider without requiring food be consumed; 3. has at least one indoor area not laid out for meals; and 4. allows drinks to be bought at a bar (i.e., not only table service)"
Read much more, including excellent historical information, from the Wikipedia aricle HERE.
