Manitou is a term used to designate spirit beings among many Algonquian groups of Native Americans. It refers to the concept of one aspect of the interconnection and balance of nature/life, similar to the East Asian concept of qi or the Hindu concept of Brahman; in simpler terms it can refer to a spirit (compare to the Japanese concept of kami). This spirit is seen as a (contactable) person as well as a concept. Everything has its own manitou - every plant, every stone, even every machine.
The term was already widespread at the time of European contact. In 1585 when Thomas Harriot recorded the first glossary of an Algonquian language, Roanoke (Pamlico), he included the word mantóac meaning "gods" (with a plural ending). Similar terms were found in nearly all of the Algonquian languages.
In some Algonquian traditions, the term Gitche Manitou is used to refer to a Great Spirit or supreme being. The term was similarly adopted by Anishnaabe Christian groups such as the Ojibwe to refer to the monotheistic God of Abrahamic tradition by extension, often due to missionary syncretism. However, the term has analogues dating back before European contact.
In the shamanistic traditions the Manitous (or manidoog or manidoowag) are connected to achieve a desired effect, like plant manitous for healing or the buffalo Manitou for a good hunt. In the Anishinaabeg tradition manidoowag are one aspect of the Great Connection. Related terms used by the Anishinaabeg are manidoowish for small animal manidoowag and manidoons for insects; both terms mean "little spirit". In some Algonquian languages such as Iynu (Montagnais) the word manituw refers to underwater creatures to whom hunters offered tobacco in order to appease them when traveling through their territories.
The name of the Canadian province of Manitoba, named for Lake Manitoba in the province, derives from the place name manitou-wapow, "strait of the Manitou" in Cree or Ojibwe, referring to The Narrows at the centre of the lake. Also Manitoulin Island means "spirit island". The Fox Indians believed that the Manitou dwelled in the stones of the sweat lodge. On heating the stove, the heat of the fire made Manitou to come out from its place in the stones. Then it proceeds out of the stones when water is sprinkled on them. It comes out in the steam and enters the body. It moves all over inside the body, driving out everything that inflicts pain. Before the Manitou returns to the stone, it imparts some of its nature to the body. That is why one feels so well after having been in the sweat lodge.