What is a peninsula?

Hint: The surface of the Earth is covered $71\%$ by water and $29\%$ by land. The earth is made up of different layers— the crust, the mantle and the core. The land surface on earth is made up of various landforms which are a result of internal processes like the movement of tectonic plates or external processes like erosion. Major landforms include mountains, plateaus and plains. A peninsula is one such landform

Complete answer:
A peninsula is a landform that is bound by water bodies on three sides or a majority of its border but connected to the mainland on one side. The surrounding water body could be continuous or different water bodies. Peninsulas are also known by other names with a specific physical feature like headland or cape which is the tapering piece of land extending into a water body, a promontory which a raised mass of land which projects into a water body and spits which are narrow passages of sand that project into a water body. Examples of other landforms are hills, canyons, valleys, etc and coastal features like islands, peninsulas, isthmus, etc. Apart from these, there are also oceanic landforms like bays, gulfs, straits, mid-oceanic ridges, etc.

Note: Some well-known peninsulas in the world are the Korean Peninsula made up of North and South Korea, the Arabian Peninsula in the Middle East, the Iberian Peninsula made up of Spain and Portugal, the Crimean Peninsula in Russia, the Indian Peninsula, the Balkan Peninsula in Eastern Europe, the Italian Peninsula, Scandinavia in north-west Europe, the Labrador Peninsula in Canada, the Alaskan Peninsula in the USA, etc.