名詞 circular:

1. an advertisement (usually printed on a page or in a leaflet) intended for wide distribution
   同義詞：handbill, bill, broadside, broadsheet, flier, flyer, throwaway

形容詞 circular:

1. having a circular shape
   同義詞：round
2. shaped like a ring
   同義詞：annular, annulate, annulated, circinate, ringed, ring-shaped, doughnut-shaped
3. marked by or moving in a circle
   同義詞：rotary

1. We can compute the circular area with radius.
   我們能用半徑計(jì)算出圓的面積。
2. A flat-bottomed, roughly circular volcanic crater of explosive origin that is often filled with water.
   小火山口一種底部平坦、大致呈圓形的火山爆發(fā)后形成的盛滿水的低洼地
3. A device for protection from the weather consisting of a collapsible, usually circular canopy mounted on a central rod.
   雨傘用來防風(fēng)雨裝置，由某在一根中心柱上的可折收的，經(jīng)常是圓形的罩蓬構(gòu)成
4. Stop giving me circular explanations and tell me what really happened.
   別拐彎抹角地解釋了，告訴我究竟發(fā)生了什么。
5. The full moon has a circular form.
   滿月呈圓形。

cir.cu.lar

adj.Abbr. cir,circ.（形容詞）縮寫 cir,circ.
Of or relating to a circle.
圓圈的：圓圈的，與圓圈有關(guān)的

Shaped like or nearly like a circle; round.
圓形的：形狀為圓或近似為圓的；圓的
Moving in or forming a circle.
進(jìn)入圓內(nèi)或形成圓的
Circuitous; roundabout:
迂回的；繞行的：
例句：
took a circular route to the office.
繞道去辦公室

Marked by reasoning in a circle:
循環(huán)論證的：表現(xiàn)出循環(huán)特征推理的：
例句：
a circular theory.
循環(huán)理論

Addressed or distributed to a large number of persons.
供傳閱的，流通的：宣揚(yáng)或發(fā)送給大批人的
n.（名詞）
A printed advertisement, directive, or notice intended for mass distribution.
印制的廣告，傳單：印成的廣告、通告或通知，用于大量的分發(fā)

來源：
Middle English circuler
中古英語 circuler
from Anglo-Norman
源自 英法語
from Latin circul3ris
源自 拉丁語 circul3ris
from circulus [circle] * see circle
源自 circulus [圓圈] *參見 circle

【引伸】
cir.cular.ity
cir.cularly
adv.（副詞）