Open English Wordnet
Nouns
(n)circulationmovement through a circuit; especially the movement of blood through the heart and blood vessels
(n)circulation(library science) the count of books that are loaned by a library over a specified period
(n)circulationnumber of copies of a newspaper or magazine that are sold“by increasing its circulation the newspaper hoped to increase its advertising”
(n)circulationfree movement or passage (as of cytoplasm within a cell or sap through a plant)“ocean circulation is an important part of global climate”, “a fan aids air circulation”