The first element of Cosby, in the Guthlaxton Hundred of Leicestershire, is uncertain. It is likely the Old Norse male personal name Kopsi or Kofsi (genitive singular Kofsa) with Kofsa– assimilated to Cossa-. Alternatively the first element could be the Old English male personal name Cos(s)a which appears in such place-names as Cosham, Hampshire, Corsham, Wilshire and Cossington, Leicestershire. The second element is Old Norse by ‘a farmstead, a village’.
