Parabol

Part of speech: noun

Definitions

1. A type of mathematical curve where any point is equidistant from a fixed point and a line
2. An expression or function that describes such a curve in algebra
3. A narrative or story conveying a moral lesson through analogy or comparison

Etymology: In Greek, "parabole" meant a placing side by side, a comparison, or something thrown beside another thing, from "para" (beside) and "ballein" (to throw). Apollonius of Perga used it for this curve in his work on conic sections. The name comes from a geometric technique called application of areas, in which a square built on one line was shown to equal a rectangle laid alongside a fixed segment. The curve was named for that comparison of areas, not for the moral story called a parable, which shares the same Greek root. The shortened form "parabol" is not standard English. It appears in some other European languages, such as Swedish, where it denotes this curve and also, in everyday speech, a satellite dish, which is shaped like the curve's reflecting surface.

Synonyms: parabola