Groin

groin, n. the part of the body on either side of the belly where the thigh joins the trunk: ( arch it. ) the angular curve formed by the cro ing of two arches.— v.t. to form into groins, to build in groins.— n. Groin′-cen′tring , the centring of timber during construction.— adj. Groined , having angular curves made by the intersection of two arches.— n. Groin′ing .— Underpitch groining , a kind of vaulting used when the main vault of a groined roof is higher than the transverse intersecting vault, as in St George's Chapel, Windsor—sometimes called Welsh groining . [Ice. grein , division, branch—grein a, to divide; Sw. gren , branch, space between the legs; Scot. graine , grane , the branch of a tree or river.]