Tealby, in the Walshcroft Wapentake of Lincolnshire, is a very difficult name. To explain the earliest recorded forms Tavelesbi and Tauelesbi in Domesday Book, it has been suggested that the first element contains the East Germanic group-name Taifali, Old English  Taflas /Taeflas, detachments of whom are recorded as early as the fifth century. Possibly, this group retained their separate identity for some time in the post-Roman period. Thus, Tealby would originally have been a simplex form of the group-names Taflas /Taeflas, although simplex group-names are rare in English place-names.

The second element Old Norse bý ‘a farmstead, a village’ was likely added to the simplex form after Scandinavian occupation of the area.