A googol is the number one followed by one hundred zeros, far larger than anything in daily experience.

The longer version

Ten raised to the hundredth power means a one followed by a hundred zeros, a figure so large that counting to it would outlast any conceivable stretch of time. Written out, it barely fills half a line, which hides its scale completely. For scale, physicists estimate the observable universe holds somewhere near ten to the eightieth particles, twenty orders of magnitude short of a googol.

The word itself started as a joke. An American mathematician asked a child in the nineteen twenties to invent a name for a huge number, and the answer stuck, later appearing in a popular book about mathematics. Powers of ten are the natural yardstick here, since each extra zero multiplies everything by ten rather than adding a fixed amount.

Where this entry sits

This section collects odd corners of mathematics, from stubborn prime numbers to counting systems older than modern schools. Expect famous constants, probability puzzles, shapes that break everyday intuition, and numbers far too large to picture. The full list sits on the Numbers and Math page, where every entry is listed in order.