A box office is a place where tickets are sold to the public for admission to a venue. Patrons may perform the transaction at a countertop, through an unblocked hole through a wall, or at a wicket. The term is frequently used, especially in the context of the film industry, as a synonym for the amount of business a particular production, such as a film or theatre show, receives.
Box office business can be measured in terms of the number of people who see it or the amount of money raised by ticket sales (revenue). The projection and analysis of these earnings is very important for the creative industries and often a source of interest for fans. This is predominant in the Hollywood movie industry.
Some complain that industry focus on profit has diminished the attention given to film as an art form. However, analysis of the financial success of films is very influential for the production and funding of future works.There are numerous websites that monitor box-office receipts and profits, such as ShowBIZ Data and Box Office Mojo. For a list of films which are major box-office hits, see List of highest-grossing films.
On average, the movie's distributor receives more than half of the revenue, with the remainder kept by the movie theater. The split varies from movie to movie, and the percentage for the distributor is generally higher in early weeks. Usually the distributor gets a percentage of the revenue after first deducting a "house allowance" or "house nut". It is also common that the distributor gets either a percentage of the gross revenue, or a higher percentage of the revenue after deducting the nut, whichever is larger. 
A box office slump is an ongoing occasion in which all major theatrical movies fail to meet expectations at the box office. The longest North American box office slump on record started in March 2005 and ended on July 10, 2005.
It is often debated of what causes a decrease in year-by-year box office revenues. Growing ticket prices as well as the rise of the home market in recent decades may be a bit of a factor, but it is usually caused by an insufficient amount of rather interesting movies, especially when compared with the year before. Although they happen every now and then, slump years are known to take place right after a certain number of boom years. The most notorious North American box office slumps of modern times took place in 1980 (-2%), 1985 (-7%), 1991 (-4.5%) and 2005 (-6.2%). However, that is only taking into account the year-by-year rise in ticket prices, and the drop in ticket sales are more recurrent than the decline in yearly revenues, although they are most severe during slump years. Examples of declines in ticket sales are found in 1980 (-9%), 1985 (-11.9%), 1986 (-3.7%), 1990 (-5.9%), 1991 (-4%), 1995 (-2.3%, 2000 (-3%) and tickets sales experienced a steady decline starting in 2003 (-3.5%), until a minor recovery took place in 2006 (+ 1.4%).
But nevertheless, a slump year is also known to deliver some of the most successful films of modern times. Films like the , Back to the Future, and led the North American box office charts of their respective years by significant margins, as well as taking enormous grosses with them.
The term box office likely refers to the office where 'boxes', private seating areas, were sold at theatres and its usage derives back to the 1780s. Theatres today still have boxes, and some cinemas and theatres refer to the best seats as box seats.
The term also possibly originates from Shakespearean times, in which boxes would be used to collect a fee. However, due to thieves, the boxes would only contain a small amount of money, and the full boxes would be placed in an office, collectively called a "Box Office".