The **salinon** (meaning 'salt-cellar' in Greek) is a geometrical figure that consists of four semicircles. It was first introduced in the *Book of Lemmas*, a work attributed to Archimedes.^{[1]}

Let *A*, *D*, *E*, and *B* be four points on a line in the plane, in that order, with *AD* = *EB*. Let *O* be the bisector of segment *AB* (and of *DE*). Draw semicircles above line *AB* with diameters *AB*, *AD*, and *EB*, and another semicircle below with diameter *DE*. A salinon is the figure bounded by these four semicircles.^{[2]}

Archimedes introduced the salinon in his *Book of Lemmas* by applying Book II, Proposition 10 of Euclid's *Elements*. Archimedes noted that "the area of the figure bounded by the circumferences of all the semicircles [is] equal to the area of the circle on CF as diameter."^{[3]}

Namely, if is the radius of large enclosing semicircle, and is the radius of the small central semicircle, then the area of the salinon is:^{[4]}

Should points *D* and *E* converge with *O*, it would form an arbelos, another one of Archimedes' creations, with symmetry along the *y*-axis.^{[3]}

**^**Heath, T. L. (1897). "On the Salinon of Archimedes".*The Journal of Philology*.**25**(50): 161–163.**^**Nelsen, Roger B. (April 2002). "Proof without words: The area of a salinon".*Mathematics Magazine*.**75**(2): 130. doi:10.2307/3219147. JSTOR 3219147.- ^
^{a}^{b}Bogomolny, Alexander. "Salinon: From Archimedes'*Book of Lemmas*".*Cut-the-knot*. Retrieved 2008-04-15. **^**Weisstein, Eric W. "Salinon".*MathWorld*.

- L’arbelos. Partie II by Hamza Khelif at www.images.math.cnrs.fr of CNRS