- an act or instance of circulating, moving in a circle or circuit, or flowing.
- the continuous movement of blood through the heart and blood vessels, which is maintained chiefly by the action of the heart, and by which nutrients, oxygen, and internal secretions are carried to and wastes are carried from the body tissues.
- any similar circuit, passage, or flow, as of the sap in plants or air currents in a room.
- the transmission or passage of anything from place to place or person to person: the circulation of a rumor; the circulation of money.
- the distribution of copies of a periodical among readers.
- the number of copies of each issue of a newspaper, magazine, etc., distributed.
- coins, notes, bills, etc., in use as money; currency.
- Library Science.
- the lending of library books and other materials.
- the number of books and materials that a library has lent.
- the processes connected with providing for the use of library materials, including reserve operations, recall, and record-keeping.
- Hydraulics. a quantity analogous to work and equal to the line integral of the component of fluid velocity about a closed contour.
- in circulation, participating actively in social or business life: After a month in the hospital, he's back in circulation.
Origin of circulation
- the transport of oxygenated blood through the arteries to the capillaries, where it nourishes the tissues, and the return of oxygen-depleted blood through the veins to the heart, where the cycle is renewed
- the flow of sap through a plant
- any movement through a closed circuit
- the spreading or transmission of something to a wider group of people or area
- (of air and water) free movement within an area or volume
- the distribution of newspapers, magazines, etc
- the number of copies of an issue of such a publication that are distributed
- library science
- a book loan, as from a library lending department
- each loan transaction of a particular book
- the total issue of library books over a specified period
- a rare term for circulating medium
- in circulation
- (of currency) serving as a medium of exchange
- (of people) active in a social or business context
mid-15c., from Middle French circulation or directly from Latin circulationem (nominative circulatio), noun of action from past participle stem of circulare "to form a circle," from circulus "small ring" (see circle (n.)). Used of blood first by William Harvey, 1620s.
- Movement in a circle or circuit, especially the movement of blood through bodily vessels as a result of the heart's pumping action.
- The flow of fluid, especially blood, through the tissues of an organism to allow for the transport and exchange of blood gases, nutrients, and waste products. In vertebrates, the circulation of blood to the tissues and back to the heart is caused by the pumping action of the heart. Oxygen-rich blood is carried away from the heart by the arteries, and oxygen-poor blood is returned to the heart by the veins. The circulation of lymph occurs in a separate system of vessels (the lymphatic system). Lymph is pumped back to the heart by the contraction of skeletal muscles.
see in circulation; out of circulation.