The term "minister" comes from a Latin word meaning a "servant" (or first servant). In some countries (such as the US, Hong Kong, the Philippines and the UK), such a person can instead known as a secretary or secretary of state.
Until the early 20th century, heads of legations were also called ministers, ie: "Minister for Cuba" or "Minister for France." For example, Sir Ernest Satow was Envoy Extraordinary and Minister Plenipotentiary to Japan, 1895-1900, then the top British diplomat in Japan. His successor, Sir Claude MacDonald, was Minister and then Ambassador from 1905 when relations between Britain and Japan were upgraded.
Some examples of ministers, see the lists below for more.
Minister of State is a title borne by politicians or officials in certain countries governed under the parliamentary system.
A "minister of state" is usually a junior minister, who is either listed as a member of the cabinet or assigned to assist a specific cabinetminister.
Republic of Ireland: A Minister of State is junior to a Minister of a Department of State or normal minister and of similar standing to a Parliamentary Secretary.