A peninsula (Latin: paeninsula from paene "almost" and insula "island") is a piece of land extending out into a body of water that is still connected to mainland or a piece of land that is bordered by water on three sides but connected to mainland, for example, the upper and lower peninsulas of the state of Michigan, the peninsula of downtown Vancouver, or the Niagara peninsula. The surrounding water is usually understood to be continuous, though not necessarily named as a single body of water. Peninsulas are not always named as such; one can also be a headland, cape, island promontory, bill, point, or spit. A point is generally considered a tapering piece of land projecting into a body of water that is less prominent than a cape. A river which courses through a very tight meander is also sometimes said to form a "peninsula" within the (almost closed) loop of water. In English, the plural of peninsula is peninsulas or, less commonly, peninsulae.
Peninsulas can be found on coastlines and in smaller bodies of water throughout the world, ranging in scale from square meters to millions of square kilometers. There's the Scandinavian Peninsula in Northern Europe, and in Southern Europe there's the Iberian Peninsula, the Italian Peninsula, and the Balkan Peninsula. Prominent peninsulas in North America include the Labrador Peninsula in Canada; the Alaska Peninsula, Olympic Peninsula, and Florida Peninsula in the United States; and in Mexico, the Baja California Peninsula and the Yucatán Peninsula. South America has the Brunswick Peninsula, and Antarctica has the Antarctic Peninsula. In Africa, there's the Horn of Africa, and in Australia, the Cape York Peninsula. Asia has the 3 largest peninsulas in the world: the Arabian Peninsula, the Indian Peninsula, and the Indochinese Peninsula.
- Editors of the American Heritage Dictionaries, ed. (2004). Word Histories and Mysteries: From Abracadabra to Zeus. Houghton Mifflin Harcourt. p. 216. ISBN 978-0547350271. OCLC 55746553.
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- "List of peninsulas". Encyclopædia Britannica, Inc. 2016. Retrieved 1 May 2016.