The first example is the name of a Jew and is probably a diminutive of Isaac in its Hebrew form (Jacobs). Cock, a common personal name still in use about 1500, may partly be from Old English Cocc or Cocca, found in place-names, although not on independent record. But as cock became a common term for a boy, it may also have been used affectionately as a personal name. Old English cocc 'cock', a nickname for one who strutted like a cock. This became a common term for a pert boy and was used of scullions, apprentices, servants, etc., and came to be attached to Christian names as a pet diminutive (Simcock, Wilcock, etc.). Forms without the article may belong here; cok is ambiguous and may be for Cook. The surname may also mean 'watchman, leader' and, according to Welsh writers, may also be from Welsh, Cornish cock 'red'. 'Dweller by the Hill', Old English cocc 'haycock, heap, hillcock'. In London it probably derived from thesign of a house or inn. Sometimes we may have middle English cock 'small ship's boat', name for a boatman, barge.