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gyrus vs. sulcus

[jahy-ruhs] / ˈdʒaɪ rəs /

noun

Anatomy.
gyri plural
  1. a convolution, especially of the brain.

[suhl-kuhs] / ˈsʌl kəs /

noun

sulci plural
  1. a furrow or groove.

  2. Anatomy. a groove or fissure, especially a fissure between two convolutions of the brain.