S

Summary

saddle (noun): a native Englishword, from the Indo-European root sed- “to sit,” as found in the English cognates sit and seat. A saddle is a seat that sits on a horse, and you sit on the saddle. In mathematics a saddle point is a point on a surface z = f(x, y) such that and are both zero yet the point is neither a relative maximum nor a relative minimum. In the vicinity of a saddle point, the surface looks a typical saddle: a vertical cross-section from front to back is concave up, while a vertical cross-section from side to side is concave down. [184]

salient (noun): from Latin salient- “jumping,” present participial stem of salire “to bound, to jump, to leap.” The Indo-European root is sel- “to jump.” Related borrowings from French are somersault and sally (forth). In mathematics a salient point is one at which two branches of a curve meet with different tangents but do not cross. Functions of the type y = |f(x)| typically have salient points wherever f(x) = 0 has a single root; as the curve passes through such a point it “jumps back up.” Compare corner and contrast cusp. [187, 146]

salinon (noun): a Greek word meaning “saltcellar,” which is a small dish in which salt is kept. The Indo-European root is sal- “salt,” which is a native English cognate. Ancient Greek saltcellars must have resembled the salinon, which is an enclosed region bounded entirely by four semicircular arcs.