/ˌkänvəˈlo͞oSHən/
Noun
1. A coiling or rolling of an organ. (biology-online.org)
2. Specifically, a gyrus of the cerebral or cerebellar cortex. (biology-online.org)
3. A coil or twist, esp. one of many. (Google Dictionary)
4. A thing that is complex and difficult to follow. (Google Dictionary)
5. The shape of something rotating; a vortex. (wiktionary.org)
Word origin: From Latin convolutus (“to roll together”), past participle of convolvere, from con- + volvere (“to roll”).