circ- +

(Latin: circle [a ring; wheel], round)

circulation
1. 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.
2. An act or instance of circulating, moving or flowing in a circle or circuit.
3. Any similar circuit, passage, or flow, as of sap in plants or air currents in a room.
4. The transmission or passage of anything from place to place or person to person; such as, the circulation of a rumor; the circulation of money.
5. The distribution of copies of a periodical among subscribers.
6. The number of copies of each issue of a newspaper, magazine, etc., distributed to those who buy such media.
7. The movement of coins, notes, bills, etc., in use as money; also known as, "currency".
8. The lending of library books and other materials or the number of books and materials that a library has loaned out to patrons.
circulator
1. A person who moves from place to place.
2. A person who circulates money, information, etc.
3. A talebearer or scandalmonger.
4. Any of various devices for circulating gases or liquids.

There are circulators both for electronic signals and for light, the latter being used in optical fiber networks.

circulatory
1. A reference to circulation.
2. Relating to the circulatory system.
circus
1. A large public entertainment, typically presented in one or more very large tents or in an outdoor or indoor arena, featuring exhibitions of pageantry, feats of skill and daring, performing animals, etc., interspersed throughout with the antics of clowns.
2. A troupe of performers; especially, a traveling troupe, that presents such entertainments, together with officials, other employees, and the company's performing animals, traveling wagons, tents, cages, and equipment.
3. A circular arena surrounded by tiers of seats, in which public entertainments are held; arena.
4. Anything resembling the Roman circus, or arena, as a natural amphitheater or a circular range of houses.

The modern circus owes its name to the amusements of ancient Roman times. The Latin word circus, which comes from the Greek word kirkos, “circle, ring”, referred to a circular or oval area enclosed by rows of seats for spectators.

In the center ring, a variety of events were held, including chariot races and gladiatorial combats, spectacles in which bloodshed and brutality were not uncommon.

Our modern circus, which dates to the end of the 18th century, was originally an equestrian spectacle, but the trick riders were soon joined in the ring by such performers as ropedancers, acrobats, and jugglers.

Even though the circular shape of the arena and the equestrian nature of some of the performances are carried over from its Roman namesake, the modern circus has little connection with its brutal namesake of long ago.

—Excerpts from The American Heritage® Dictionary of the English Language, 4th Edition.
encircle (verb), encircles; encircled; encircling
1. To form a circle around someone or something.
2. To move or to go around completely; to make a circuit of.

Related "around, round, surrounding" units: ambi-; ampho-; circum-; cyclo-, -cycle; gyro-; peri-.