noun

• Synonym of heart (“the seat of the affections or love”)
• Also in the plural form heartlands:
• The interior part of a region, especially when contrasted with coastal parts or when regarded as particularly powerful or significant.
• (specifically) In the geopolitical theory of the English geographer Halford John Mackinder (1861–1947): the interior of the world island comprising north-central Eurasia regarded as politically powerful.
• (specifically, Singapore, chiefly in the plural) Residential districts and planning areas outside the city centre; the new towns of Singapore collectively.
• (specifically, US, often attributively) The states in the centre of the United States, chiefly regarded as politically and socially conservative; also, the people living in such states collectively.
• A region or part of a region particularly associated with or significant for a characteristic, such as an activity, a faith, support for a political party or other organization, etc.