circular

adj

1. Of or relating to a circle.
2. 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.”

3. Circuitous or roundabout.
4. 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.”

   “a circular formula in a spreadsheet”

   “It must be conceded that this definition (the definition of tort) is somewhat circular, but it is the only one that will suffice.”

5. Distributed to a large number of persons.

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

6. (obsolete)Perfect; complete.

   “A man so absolute and circular / In all those wished-for rarities that may take / A virgin captive.”

7. (archaic)Adhering to a fixed circle of legends; cyclic; hence, mean; inferior.

   “February 1, 1711, John Dennis, on the Genius and Writings of Shakespeare Had Virgil been a circular poet, and closely adhered to history, how could the Romans have had Dido?”

noun

1. An advertisement, directive or notice intended for mass circulation.

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

2. (abbreviation, alt-of, ellipsis)Ellipsis of circular letter.
3. (abbreviation, alt-of, ellipsis)Ellipsis of circular file.
4. (dated)A sleeveless cloak cut from a circular pattern.
5. A shuttle bus with a circular route.

verb

1. 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.”

   “I do not mean to say we have never employed some of them who come to us—but we have never circulared agents or gone after them.”

   “If you've ever been circulared by drug repackaging houses, you know they usually offer to trade a selection of office supplies for your unused drug samples.”

2. 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.”