circulation meaning
EN
[ˈsɜː(ɹ).kjʊˌleɪ.ʃən] [ˈsɝkjʊˌleɪʃən] [-eɪʃən] 
US WCirculation
- Circulation may refer to:
- Circulatory system, a biological organ system whose primary function is to move substances to and from cells
- Circulation (fluid dynamics), the path integral of the fluid velocity around a closed curve
- Circulation (journal), one of the journals published by American Heart Association
- Circulation (architecture), the flow of people through a building
- Exhaust gas recirculation, a nitrogen oxide reduction technique used in most gasoline and diesel engines
- Atmospheric circulation, the large-scale movement of air
FR circulation 
- NounPLcirculationsSUF-ation
- The act of moving in a circle, or in a course which brings the moving body to the place where its motion began.
- The act of passing from place to place or person to person; free diffusion; transmission.
- Currency; circulating coin; notes, bills, etc., current for coin.
- The extent to which anything circulates or is circulated; the measure of diffusion; as, the circulation of a newspaper.
- The movement of the blood in the blood-vascular system, by which it is brought into close relations with almost every living elementary constituent. Also the movement of the sap in the vessels and tissues of plants.
- The act of moving in a circle, or in a course which brings the moving body to the place where its motion began.
- More Examples
- Used in the Middle of Sentence
- The hot-and-cold-water treatment Sweetie referred to is called kneipping: you put your feet or your wrists or your shins in water to force your circulation to speed up.
- Used in the Ending of Sentence
- It is also resecreted into the gastrointestinal tract through enterohepatic circulation.
- For blood vessel-borne metastasis, disseminated tumor cells (DTCs) intravasate into blood vessels and survive in the circulation.
- To my small hands, the bitter wind cuts like a knife, freezing my fingers and numbing my circulation.
- Used in the Middle of Sentence
Definition of circulation in English Dictionary
- Part-of-Speech Hierarchy
- Nouns
- Countable nouns
- Singularia tantum
- Uncountable nouns
- Uncountable nouns
- Countable nouns
- Nouns
Source: Wiktionary
Grammatically, this word "circulation" is a noun, more specifically, a countable noun and a singularia tantum.