The first element of Grainsby, in the Haverstoe Wapentake of Lincolnshire, is of uncertain origin. It is likely the Old Norse male byname Grein, Old East Scandinavian Gren, from Old Norse grein, Old Danish gren ‘a branch’. Alternatively the element could be the Old Norse appellative grein ‘a branch (of a tree); a fork (of a river)’. This word survives in dialect as ‘a small valley forking off from another’, but there is nothing in the topography of Grainsby that supports this sense. The second element is Old Norse by ‘a farmstead, a village’.
