sulcus

A deep, narrow furrow or groove, as in an organ or tissue.

Any of the narrow fissures separating adjacent convolutions of the brain.

A furrow or groove; a more or less linear or narrow and shallow depression; specifically, in anatomy, a fissure between two gyri or convolutions of the surface of the brain: used with English or Latin context. See phrases under fissure, and cuts under brain, cerebral, and gyrus.

A furrow; a groove; a fissure.

a furrow or groove in an organ or a tissue

any of the grooves that mark the convolutions of the surface of the brain

subparallel grooves and ditches formed by geological processes

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