/ ˌsɜːkjəˈleɪʃn; NAmE ˌsɜːrk-/ noun
1.
the movement of blood around the body :
Regular exercise will improve blood circulation.
to have good / bad circulation
2.
[ U ] the passing or spreading of sth from one person or place to another :
the circulation of money / information / ideas
A number of forged tickets are in circulation .
The coins were taken out of circulation .
Copies of the magazine were withdrawn from circulation .
3.
[ U ] the fact that sb takes part in social activities at a particular time :
Anne has been ill but now she's back in circulation .
I was out of circulation for months after the baby was born.
4.
[ C , usually sing. ] the usual number of copies of a newspaper or magazine that are sold each day, week, etc. :
a daily circulation of more than one million
5.
[ U , C ] the movement of sth (for example air, water, gas, etc.) around an area or inside a system or machine
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WORD ORIGIN
late Middle English (denoting continuous distillation of a liquid): from Latin circulatio(n-) , from the verb circulare , from circulus small ring, diminutive of circus ring.