Here is a booby-prize definition of mathematics: Mathematics is the science which uses easy words for hard ideas.
A simple curve is a closed curve which does not cross itself.
A French mathematician, Jordan, gave the fundamental theorem: every simple curve has one inside and one outside. That is, every simple curve divides the plane into two regions, one inside the curve, and one outside.
其它几个数学词汇的例子： function, turbine, circle, parhexagon, and radical, etc.
数学概念中天文数字 googol 与 googolplex 的意义。 这些数字 was finite, not infinite.
The name “googol” was invented by a child (Dr. Kasner’s nine-year-old nephew) who was asked to think up a name for a very big number, namely, 1 with a hundred zeros after it.
数学中的新名词， 如 mathescope，
The mathescope is not a physical instrument; it is a purely intellectual instrument, the ever-increasing insight which mathematics gives into the fairyland which lies beyond intuition and beyond imagination.
(GGB, Vol. 9, pp. 121-136; originally chapter 1 of Mathematics and the Imagination)