groin

n. [ Icel. grein distinction, division, branch; akin to Sw. gren, branch, space between the legs, Icel. greina to distinguish, divide, Sw. grena to branch, straddle. Cf. Grain a branch. ] 1. (Anat.) The line between the lower part of the abdomen and the thigh, or the region of this line; the inguen. [ 1913 Webster ]

2. (Arch.) The projecting solid angle formed by the meeting of two vaults, growing more obtuse as it approaches the summit. [ 1913 Webster ]

3. (Math.) The surface formed by two such vaults. [ 1913 Webster ]

4. A frame of woodwork across a beach to accumulate and retain shingle. [ Eng. ] Weale. [ 1913 Webster ]

v. t. [ imp. & p. p. Groined p. pr. & vb. n. Groining. ] (Arch.) To fashion into groins; to build with groins. [ 1913 Webster ]

The hand that rounded Peter's dome,
And groined the aisles of Christian Rome,
Wrought in a sad sincerity. Emerson. [ 1913 Webster ]

n. [ F. groin, fr. grogner to grunt, L. grunnire. ] The snout of a swine. [ Obs. ] Chaucer. [ 1913 Webster ]