'Sulcus' definitions:

Definition of 'sulcus'

(from WordNet)
noun
(anatomy) any of the narrow grooves in an organ or tissue especially those that mark the convolutions on the surface of the brain

Definition of 'Sulcus'

From: GCIDE
  • Sulcus \Sul"cus\, n.; pl. Sulci. [L., a furrow.] A furrow; a groove; a fissure. [1913 Webster]