A Convolution

1. A twist or fold.
2. Any of the folds on the surface of the brain.
3. The shape of something rotating; a vortex.
4. State or condition of being convoluted.
5. (mathematics) A form of moving average. Convolution - Wikipedia
6. (computing) A function which maps a tuple of sequences into a sequence of tuples.
7. One 360° turn in a spring or similar helix. A keyring contains 2 convolutions.