E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Morther.
Well, Mor, where have you been this long while? (Norfolk). Isy, Mor, come hither! (Norfolk). Mor or Morther means a lass, a wench. It is the Dutch moer (a woman). In Norfolk they call a lad a bor, from the Dutch boer (a farmer), English boor. Well, bor! and Well, mor! are to be heard daily in every part of the county.