• Karewas are lacustrine deposits [deposits in lakes] in the Valley of Kashmir and in Bhadarwah Valley of the Jammu Division. The Karewa Formation is a Plio-Pleistocene glaciofluvial-lacustrine and aeolian loess.  It is critical for agricultural and horticultural practices.
• A barchan or barkhan dune is a crescent-shaped dune. The term was introduced in 1881 by Russian naturalist Alexander von Middendorf, for crescent-shaped sand dunes in Turkestan and other inland desert regions. Barchans face the wind, appearing convex and are produced by wind action predominantly from one direction.
• Kayals are defined as the shallow lagoons or inlets of sea that are parallel to the coastallines. The lagoon lakes in Kerala are known as Kayal. Word Kayal means backwater. Kerala backwaters are a network of brackish lagoons and lakes.

Source: NCERT- Indian Physical Geography