I. ˈgrȯin noun
Etymology: alteration of Middle English grynde, from Old English, abyss; akin to Old English grund ground
Date: circa 1532
1. : the fold or depression marking the juncture of the lower abdomen and the inner part of the thigh ; also : the region of this line
2.
a. : the projecting curved line along which two intersecting vaults meet
b. : a rib that covers this edge
3. : a rigid structure built out from a shore to protect the shore from erosion, to trap sand, or to direct a current for scouring a channel
[
groin 2a
]
II. transitive verb
Date: circa 1816
: to build or equip with groins