From Middle English circuler, circuleer, circulere, from Old French circulier, from Late Latin circularis, from Latin circulus, diminutive of circus.

• (RP, Australia) IPA: /ˈsɜː.kjə.lə(ɹ)/
• (America) IPA: /ˈsɝ.kjə.lɚ/

circular

1. Of or relating to a circle.
2. In the shape of, or moving in a circle.
   • 1918, W[illiam] B[abington] Maxwell, chapter V, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC ↗:

     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

   I changed the definition of "sex" from "to have sex" to "to have sexual intercourse"; a dictionary definition must never be circular; using the word being defined to define itself.

5. Distributed to a large number of persons.
   • 1827, Henry Hallam, The Constitutional History of England from the Accession of Henry VII. to the Death of George II. […], volume (please specify |volume=I or II), London: John Murray, […], →OCLC ↗:

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

6. (obsolete) Perfect; complete.
7. (archaic) Adhering to a fixed circle of legends; cyclic; hence, mean; inferior.
   • February 1, 1711, John Dennis (dramatist), 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?

• ringlike
• ring-shaped
• round-like

• French: circulaire
• German: Kreis
• Italian: circolare
• Portuguese: circular
• Russian: кругово́й
• Spanish: circular

• French: rond
• German: rund, Kreis, kreisartig, kreisförmig, kreisend (moving in a circle)
• Italian: circolare
• Portuguese: circular, redondo, arredondado
• Russian: кру́глый
• Spanish: circular

• Portuguese: circular
• Russian: око́льный

• German: zirkelhaft

• Russian: циркуля́рный

circular (plural circulars)

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

   Synonyms: flyer

   • 1991 September, Stephen Fry, chapter 2, in The Liar, London: Heinemann, →ISBN, →OCLC ↗, section I, page 40 ↗:

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

2. Short for circular letter.
3. Short for circular file.
4. (dated) A sleeveless cloak cut from a circular pattern.
5. A shuttle bus with a circular route.

• French: circulaire
• Russian: циркуля́р

circular (circulars, present participle circularing; simple past and past participle circulared)

1. To distribute circulars to or at.
2. To extend in a circular direction.