/groyn/ , n.
1. Anat. the fold or hollow on either side of the front of the body where the thigh joins the abdomen.
2. the general region of this fold or hollow.
3. Archit. the curved line or edge formed by the intersection of two vaults. See illus. under vault 1 .
4. Also, groyne . a small jetty extending from a shore to prevent beach erosion.
v.t.
5. Archit. to form with groins.
[ 1350-1400; earlier grine, ME grinde; cf. OE grynde abyss, akin to grund bottom, GROUND 1 ]