A governor or governour (archaic) is a governing official, usually the executive (at least nominally, to different degrees also politically and administratively) of a non-sovereign level of government, ranking under the Head of state; furthermore the title applies to officials with a similar mandate as representatives of a chartered company which has been granted exercise of sovereignty, even with its own armed forces, in a colonial area, often both colonizing and exploiting, sometimes a major state within the state, such as the British HEIC or the Dutch VOC.
In federations a governor can be the title of each appointed or (as in the US) elected politician who governs a constitutive state. Most countries in the world have some sort of official known or rendered as "governor," though in some countries the heads of the constitutive states, provinces, communities and regions may have a different title. This is particularly common in European nations and many of their former colonies, with titles such as President of the Regional Council in France and minister-president in Germany. Other countries using different titles for sub-national units include Spain, Italy and Switzerland.
There can also be non-political governors: high ranking officials in private or similar governance such as commercial and non-profit management, styled governor(s), who simply govern an institution, such as a corporation or a bank. For example, in the United Kingdom and other Commonwealth countries there are prison governors ("warden" in the United States), school governors and bank governors.