groin (Noun) — The crease at the junction of the inner part of the thigh with the trunk together with the adjacent region and often including the external genitals.
groin (Noun) — A curved edge formed by two intersecting vaults.
groin (Noun) — A protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away.
groin (Verb) — (construction) build with groins. ex. "The ceiling was groined"