limaçon (English spelling) limacon

…For a moving point Q on the line x = a , if you take a line segment QP of length b on the line OQ on both sides of Q, P will draw this curve. (3) A quartic curve expressed by the equation ( x ² + y ² - ax ) ² = b ² ( x ² + y ² ) ( a , b are positive constants) is called a limaçon or a cochlear line (Figure 7). If you take a moving point Q on the circumference of a circle whose diameter is the line segment connecting the origin O and A ( a , 0), and take a line segment QP of length b on the line OQ on both sides of Q, P will draw this curve. …

*Some of the terminology explanations that mention "limaçon" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…直線x＝a上の動点Qに対し，直線OQ上に長さbの線分QPをQの両側にとれば，Pはこの曲線を描く。(3)方程式(x²＋y²－ax)²＝b²(x²＋y²)(a,bは正の定数)で表される四次曲線をリマソンlimaçonまたは蝸牛（かぎゆう）線という(図7)。原点OとA(a,0)を結ぶ線分を直径とする円周上に動点Qをとり，直線OQ上に長さbの線分QPをQの両側にとるとき，Pはこの曲線を描く。…

※「limaçon」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報