fraction

[bbeeton]

By itself, in a non-mathematical sense, this indicates a part of something. It also forms a part of other words: refraction, diffraction, infraction.

Somewhat related etymologically, fractal describes a shape that is formed of innumerable self-similar parts.

In the 1950s, diffraction gratings -- surfaces ruled with very fine closely-spaced lines -- were formed into subtly flashy jewelry; they made very nice cufflinks, of which I still have a pair. I'm trying to picture a Mandelbrot set (perhaps the canonical fractal curve) machined as a diffraction grating. I suspect it would be pretty eye-catching.

[Slava]

Touched upon in the treatment of fractious.

Here's Wikipedia's entry on diffraction grating.