circular

Of or relating to a circle.

In the shape of, or moving in, a circle.

Near-synonyms: oval; round; toroid, ringlike, round-like

Here, in the transept and choir, where the service was being held, one was conscious every moment of an increasing brightness; colours glowing vividly beneath the circular chandeliers, and the rows of small lights on the choristers' desks flashed and sparkled in front of the boys' faces, deep linen collars, and red neckbands.

Circuitous or roundabout.

Referring back to itself, so as to prevent computation or comprehension; infinitely recursive.

circular reasoning

Your dictionary defines "brave" as "courageous", and "courageous" as "brave". That's a circular definition.

Distributed to a large number of persons.

a proclamation of Henry III., […] doubtless circular throughout England

An advertisement, directive or notice intended for mass circulation.

The pigeon-hole was also stuffed with circulars and hand-bills.

Ellipsis of circular letter.

Ellipsis of circular file.

A sleeveless cloak cut from a circular pattern.

A shuttle bus with a circular route.

To distribute circulars to or at.

The result of the sending of these notices confirms me in the opinion, that it will be necessary to adopt legal means with the great majority of these parties. The circulars have had little effect. In fact, the parties have been “circulared" into the notion that nothing more formidable will ever be sent to them.

It is true, that, to obtain these, some six hundred or more institutions were circulared, and a good many of these a second time.

To extend in a circular direction.

The theme can be expressed in an architectural analogy. For, of all contriving to encover space, the arch — alone or 'circulared' into the dome — is the most ingenious.