noun

1. the hollow or fold where the abdomen joins either thigh
2. Archit.
   1. the sharp, curved edge formed at the junction of two intersecting vaults
   2. the rib of wood, stone, etc. covering this edge
3. a strong, low sea wall built at a right angle to the coast to reduce shoreline erosion, esp. of a beach

Etymology: Early ModE phonetic rendering of grine, var. of grinde < ME grynde, prob. < OE, abyss, in sense “depression” (akin to grund, ground)

transitive verb