Ham is the term used to describe cured and cooked pork. It is generally the hind leg of a pig; shoulder is used too but this is not technically 'ham'. More confusingly, it also refers to cured hind leg that has been air-dried and is usually sliced very thinly and served cold. Both can be smoked or left green after curing.
Examples of traditionally cured hams:
York Ham: a rich salty ham, with distinct pork flavour and a dry texture. It is not smoked after curing.
Cumberland Ham: when cooked this ham has a deep, pronounced ham flavour that is slightly spicy and heavily salted. Not to be confused with Cumbria Air-Dried Ham for which a similar cure is used but it is air-dried and so can be eaten raw.
Bradenham Ham: an unsmoked cured ham from Wiltshire with a delicate, sweet and mild flavour thanks to the marinade of molasses and spices.