circulation Definition

circulation
noun

1. The act or process of circulating.
2. anatomy.
In most animals: the system of blood vessels that supplies oxygenated blood pumped by the heart to all parts of the body, and that transports deoxygenated blood to the lungs.
3a. The distribution of a newspaper or magazine;
3b. The number of copies of it that are sold.

Idiom: in circulation (out of circulation)

Said of money: being, or not being, used by the public.

Taking part, or not taking part, in one's usual social activities.