Circulation may refer to:

Science and technology

Atmospheric circulation Atmospheric circulation is the large-scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies from year to year, bu ...

, the large-scale movement of air *

Circulation (physics) In physics, circulation is the line integral of a vector field around a closed curve. In fluid dynamics, the field is the fluid velocity field. In electrodynamics, it can be the electric or the magnetic field. Circulation was first used independ ...

, the path integral of the fluid velocity around a closed curve in a fluid flow field *

Circulatory system The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...

, a biological organ system whose primary function is to move substances to and from cells *

Circulation problem The circulation problem and its variants are a generalisation of network flow problems, with the added constraint of a lower bound on edge flows, and with flow conservation also being required for the source and sink (i.e. there are no special node ...

, a generalization of network flow problems *

Circulation (architecture) In architecture, circulation refers to the way people move through and interact with a building.http://www.britannica.com/EBchecked/topic/118392/circulation "circulation (architecture)" in Britannica Online Encyclopedia In public buildings, circulat ...

, the flow of people through a building *

Circulation (currency) In monetary economics, the currency in circulation in a country is the value of currency or cash (banknotes and coins) that has ever been issued by the country’s monetary authority less the amount that has been removed. More broadly, money in c ...

, all currency held by consumers and businesses, but not by financial institutions and governments *

Exhaust gas recirculation In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide () emissions reduction technique used in petrol/gasoline, diesel engines and some hydrogen engines. EGR works by recirculating a portion of an engine's exhaust ...

, a nitrogen oxide reduction technique used in most gasoline and diesel engines * Library circulation, the activities around the lending of library books and other material to users of a lending library *

Rhetorical circulation Rhetorical circulation is a concept referring to the ways that texts and discourses move through time and space. The concept seems to have been applied to texts sometime in the mid 1800s, and it is considered, by most scholars, to be either subordin ...

, the ways that texts and discourses move through time and space

Other uses

Newspaper circulation Print circulation is the average number of copies of a publication. The number of copies of a non-periodical publication (such as a book) are usually called print run. Circulation is not always the same as copies sold, often called paid circulat ...

, the average number of copies of a newspaper distributed on a day * Magazine circulation, the average number of copies of a periodical distributed per edition/ volume * Circulation Festival, an annual circus and fire performance festival held in Dunedin, New Zealand * ''Circulation'' (film), a 2008 psychological thriller-fantasy film by Ryan Harper * ''Circulation'' (journal), a journal published by the American Heart Association {{disambig